Philosophy can be defined as a form of knowledge that, despite the wide variety of its expressions, exhibits as almost constant characteristics two vocations: one towards universality and one towards the prescription of wisdom. The former manifests itself in two ways: philosophy is presented as the perfect form of knowledge, in any case as the best possible form of knowledge for mankind, compared to other inferior ones, or at least as the most general and comprehensive form of knowledge; or it is presented as a knowledge that takes other forms of knowledge as its subject, to study their characteristics, their areas of validity, their implicit meanings.

In both cases, philosophy ends up involving all forms of human activity, which it critically examines within the individual fields identified by the current denominations of different philosophical disciplines: logic, ethics, metaphysics, aesthetics, the philosophy of history, of law, of religion, of nature, of science, and so on. The vocation towards the prescription of wisdom is presented as the code of conduct that conforms to the results of philosophical research.

The search for the principle of things

In the oldest manifestations of western tradition, philosophy presents itself as a science, or rather as the science par excellence, and it examines the origins and the structure of things. A common aspect to all philosophers is the search for the first principle of reality, for whatever exists as the foundation of the variety of phenomena and renders it intelligible. According to the Aristotelian testament, for the majority of the first philosophers, this principle is materialistic: in Thales, for example, water is the common principle of all things. But Anaximander goes beyond this understanding of a material principle and recognizes the ‘principle’ in an undeterminable reality, which he calls the limitless and in which he sees the cause of the creation and destruction of beings, that happens based on necessity.

The theme of cosmic legality is thus outlined, the unitary meaning to the variety of phenomena. This theme is found again in Heraclitus with the notion of the logos as the law of existence and as the rule to the opposing conflicts that form the flow of life. In Heraclitus, we also find the distinction between a vulgar knowledge and an authentic knowledge, the former belonging to the many, the latter belonging to the philosopher, or to the sage who, underneath the appearances, knows the true nature of things. With Parmenides of Elea, there is a clear distinction, or rather a juxtaposition, between truth and opinion, correlative to an evaluation of reality, of which the authentic and truly real substance is the being, what is opposed to the fickle and unstable world of becoming. With this, the concept was created of a reality that was superior, transphenomenal, deductible from reality, in antithesis with the world of ordinary experience, recognized by the senses.

Philosophy as “first science”

Towards the middle of the 5th century BC, the focus of philosophical research moves towards anthropological issues (knowledge, morality). The protagonists of this new school are the so-called sophists, to whom we also owe the critique of a series of traditional notions. Philosophy becomes critical of tradition, in its religious, ethical, juridical, and political aspects. Tradition and its certainties are replaced by debate (hence the vital importance of rhetoric, of the art of saying and persuading), with a strong relativistic accent. But in order for the debate to be fruitful, we need to have criteria, to give meaning to words, to define them. And this is the necessity brought forth by Socrates, a sophist as well by virtue of being the creator of debate and criticism, but an enemy of the sophists and more radical than them as a supporter of a correct and cohesive debate. Hence Aristotle’s judgment, according to whom Socrates is the inventor of the ‘concept’ or of the ‘universal’.

In Plato, different characterizations of philosophy, implicit or explicit, coexist. In the Symposium we find the acceptation of the word (‘love of knowledge’, and ϕιλοσοϕεῖν with the meaning of ‘examining’ and ‘researching’). Plato gives a typical representation of the philosopher who is only interested in scientific studies and uncaring of what pertains to practical life in the Theaetetus. The philosopher of the Theaetetus is also a mathematician and an astronomer: he discovers the very structure of the being. And in the Sophist, the philosopher is identified with the debater, as the dialectic is not just a research method or a spiritual exercise, but the objective nexus that holds the connections between ideas.

Aristotle confirms the platonic idea of philosophy as the science par excellence, superior in-depth to all other sciences. The sciences study their subjects within their necessary or more constant characteristics, while philosophy examines them in their most intimate essence, in what they have of substantial and that makes them what they truly are. Therefore, philosophy establishes the foundations of all other sciences. In this specific sense Aristotle defines philosophy as first science or first philosophy or even theology, and places it alongside the other sciences he calls theoretical, mathematics, and physics, but in a privileged position compared to them.

Philosophy as the practice of wisdom

The theme of philosophy as the search and practice of wisdom presents itself in its most specific form in the Epicurean and Stoic schools, and it can also be found in the Cynics, the Cyrenaics, and the Sceptics. The new accent gained by philosophy lies within the assumption that truth exists in the function of the self and that reaching individual happiness (and independence) is the most important objective in life. These philosophies rise in conjunction with the crisis of the ancient city and they express the desire of the individual to retire inside their personal peace. However, philosophy isn’t thus reduced to ethics; Epicureans consider both physics and the canon (theory of knowledge) to be its necessary premises, and even the stoics place logic and physics alongside ethics. Still, the aim is to achieve the happiness-serenity of the individual.

These forms of rational wisdom will soon be overtaken by typically religious wisdom, hence concerning not only happiness but rather individual salvation. And philosophy gains a religious and soteriological nuance: philosophy begins to be identified in religion, since the search for truth doesn’t seem to be achievable through a logical-rational examination, but it tries to be fulfilled in the form of a superior knowledge (γνῶσις) that stems from ineffable and divine realities. A strong religious inspiration crosses Neoplatonism, which will mainly try to present itself as a return to Plato: the transcendence of divinity, the division between the tangible and intangible world, but with a dynamic connection between the two in the context of more profound unity. In the later Neoplatonists, the assimilation of pagan mythology and mysterious, magical rituals will become more and more prominent.

Humanism and Renaissance

With Humanism and the Renaissance, philosophy continues to be a form of totalizing knowledge; however, its accent changes, because it begins to assume those characteristics of mundanity that are generally thought of when we speak of modern thought. As such, it is essentially focused on the earth, the individual, the historian, all interests obviously not absent in medieval philosophy and culture, but clearly surpassed by the interest in the transcendent. Nor, on the other hand, can one say that the philosophy of Humanism and the Renaissance is an irreligious philosophy. But religious necessity springs from the very dignity of the man himself, from his excellence before other creatures, from his centrality in the universe, from his being made in the image of God. The new attitude is manifested in the rediscovery of the classics, in the controversy against scholastic logic, in the controversy against theological dispute. The rediscovery of the classics is not a simple philological rediscovery, but more importantly their ‘imitation’ and at the same time the creation of a new ideal of life, taken from those models.

The polemic against scholastic (and Aristotelian) logic is configured as a polemic against an abstract discipline, in the sense of being artificial and useless for research. The polemic against theological dispute is also polemic against insubstantial and gratuitous mental contrivances. These forms of ‘abstractness’ are contrasted on the one hand by attempts at different logics, closer to the concrete processes of the mind and the psychological knowledge of man, and on the other by the concrete religious experience as lived by the believer. In this way, the principle of tolerance is affirmed, deduced from the importance of the characteristics common to the various faiths and from the inessentiality of the differential and contrasting elements.

Modern philosophy

In Francis Bacon, we find, as in the whole Renaissance, the ideal of the regnum hominis, of the rational domination of nature, which is the purpose of knowledge and also of the practical organization of knowledge. Bacon offers an encyclopedia of the different forms of knowledge, an organic arrangement of the different sciences. We have a philosophy understood as rational knowledge and including various disciplines, and philosophy in the strictest sense or first philosophy, including the more general notions, i.e. the valid axioms for different sciences.

Modern philosophy, therefore, develops in close connection with the sciences, to which its relationship is dual: on the one hand, philosophy wants to imitate their methodical rigor and, from this point of view, to become a science itself; on the other hand, it claims to have its own specific field of investigation that establishes the foundations of sciences. R. Descartes says that it is ‘first’ philosophy, dedicated to more general notions. From this the image of knowledge as that of a tree, « the roots of which are the metaphysics, the trunk is physics, and the branches rising from this trunk are all the sciences».

T. Hobbes, B. Spinoza, G.W. Leibniz conceive philosophy according to an analogous rationalistic scheme, i.e. as the science that studies the ultimate reasons for phenomena, using a rigorous method borrowed from mathematics. But while in Leibniz there is a theological recovery, in Hobbes and Spinoza we find a clear separation of philosophy and theology, because theology concerns notions not subject to rational analysis and because its object is faith, whose purpose is obedience and piety, and not the truth, which is the only purpose of philosophy.

With J. Locke philosophy takes as its essential task the examination of the validity and the limits of knowledge, thus becoming a critical philosophy. Before proceeding to the construction of metaphysical buildings it is necessary to analyze our ability to know. The result of the investigation is that experience is the foundation and origin of all our knowledge, and thus the methodical basis of philosophy.

Enlightenment and Kant

Locke’s lesson was a lesson in critical caution, and in this sense, his philosophy was interpreted by the Enlightenment. «After so much unfortunate wandering – wrote Voltaire – tired, exhausted and shameful of having sought so many truths and found so many chimeras, I returned, like the prodigal son to his father, to Locke; and I threw myself into the arms of a modest man, who never pretends to know what he does not know, who does not possess, in truth, immense wealth, but whose funds are secure, and who enjoys without ostentation the most solid possessions.» Similar praise can be read in the Preliminary Discourse to the Encyclopedia, written by d’Alembert: it can be said that Locke – says d’Alembert – «created metaphysics, just as Newton created physics». And this metaphysics is «what it effectively must be, the experimental physics of the soul». A, therefore ‘reasonable’ metaphysics, no longer participating in the ‘ spirit of system ‘ of metaphysical constructionism. Illuministic knowledge is aimed at practical purposes (another Baconian motif), it is an eminently ‘useful’ knowledge. And philosophy is considered (and lived) as an essential factor of demystification, liberation, and progress.

The polemic against metaphysical constructions continues in I. Kant, and in him, it reaches its definitive form. Kant defines as dogmatic all metaphysics that does not presuppose a criticism of the ability to know. The wrong of these metaphysics has been to have ventured into the field of the supersensible, without taking into account the fact that no knowledge is possible without the intervention of sensitivity, which alone can attest to the presence of the known object. In the face of such constructions, the onset of skepticism is inevitable, which moreover limits itself to detecting the failures of reason, but without a previous criticism of it.

Kant provides this criticism, in which he establishes the limits of validity of the operations of the mind, as well as describing the structure of the mind itself. The result of the criticism is that it limits the scope of scientific knowledge and knowledge in general to the world of phenomena, but leaves open the traditional (and ineliminable for it is inherent to man) field of metaphysics to a different use of reason, the practical one. In this field, man encounters the problems of the freedom of will, the immortality of the soul, the existence of God, and resolves them positively according to the rationality of the moral principles that regulate (‘must’ regulate) actions. It is not a theoretical solution (a knowledge), impossible given the results of the criticism, but a practical solution, a practical certainty. Thus we have two worlds, the world of nature with its scientific laws and the world of freedom with its rational faith and its access to the supersensible.

The conciliation between these two worlds is possible through the use of judgment, which ponders on the purposes it encounters in nature and thinks them according to the principle of an intentional causality that would act in nature itself. Finalism, however, is a principle of exposition and understanding, not of explanation: the conciliation of the two worlds, sensible and supersensible, while legitimate and somehow necessary to man, remains hypothetical and problematic. A world in harmony with moral action is conceivable through a form of judgment different from that of scientific ones: such judgment does not grasp the essence of things but hypothesizes that it is sensible. This insistence on the ‘as if’ from Kant is due to his concern not to give value a status similar to that of fact and thus fall into a form of determinism and thus to compromise the autonomy of the reason and the freedom of man.

German idealism

Referring back to Kant, J.G. Fichte affirms the superiority of value over fact, of having to be over being: the practical foundation is placed at the basis of philosophizing, and human freedom, and therefore the “I” as the principle of philosophy, is a faith. For G.W.F. Hegel the point of view of the absolute, that is, of science, is not immediately obtained, but it presupposes the path that human consciousness takes from the most elementary to the most complex forms until it reaches a degree of awareness that allows it to practice science. This description is the subject of the Phenomenology, which follows a series of experiences, through which man conquers the awareness of his freedom, i.e. he gets rid of the object as something foreign and mysterious and feels this world as his own. Having reached this awareness, he rethinks the path and enucleates from it the concepts matured through those experiences.

The logic and philosophy of nature and spirit are precisely the results of these elaborations. And this is what gives rise to the absolute knowledge, a knowledge that has its measure only in itself, and that is historical knowledge, well anchored in time. It discovers that the path traveled by humanity is a sensible one, that has achieved the progressive awareness of human freedom and is therefore rational. The concepts of philosophy are the expression of this rationality, which is therefore not the result of an act of the mind, but it is an objective, realized rationality reflected by thought. Of course, this does not mean that everything that exists is rational: the rational is what is most significant in reality, it is the bearer of meaning. And meaning is precisely given by that process where man has acquired the awareness of his freedom. From this point of view, Hegelian philosophy is an interpretation of the historical course. To philosophize is, therefore, to understand what has been: «philosophy is one’s own time learned through thought».

Philosophy and science in positivism

For A. Comte philosophy is, first of all, a reflection on knowledge and thus an analysis of the tendencies and techniques of the various sciences, classified according to an order of decreasing generality; not only that but at times some of their criteria are prescribed to be followed, as those that best respond to their internal logic, that is, to the implementation of their ‘positivity’. Positivity means overcoming the two previous phases of the development of the intellect (theology, metaphysics); a science is positive when it radically renounces the search for causes and establishes laws, or the constant relations between phenomena, makes predictions, is socially useful. In H. Spencer philosophy is the most general form of knowledge, unifying the sciences and pertaining to notions with the most extensive content.

The reaction to positivism

For H. Bergson, on the other hand, philosophy is not a generalizing science, nor a reflection on the sciences, but a mental operation that puts us in a different relationship with things rather than the one in which science places us. Philosophy and science do not compete in grasping reality, but, if anything, they collaborate because they refer to two fundamental aspects of reality itself. Science and metaphysics – says Bergson – have different subjects: «to science the matter and to metaphysics the spirit». But science and metaphysics have intuition in common, which grasps reality in its fullness: in fact, for what they have of essential, in their authentic discoveries, they have proceeded by intuition.

It is the atmosphere of the reaction to positivism, a reaction that reclaims the autonomy of philosophy and seeks a way of approaching reality that is not the generalizing one of law and of type. For W. Windelband as well, philosophy has its own sphere of autonomy as a critical science of universally valid values.

In E. Husserl, the idea of philosophy as a rigorous science reemerges: the essences, which according to his method are intuited, are neither facts nor abstractions taken from facts, but have the characteristic of purity, comparable to mathematical notions. Therefore, a strong anti-relativistic accent, and yet a strong anti-objectivist accent: the objectivism of science has something dogmatic if it claims to exhaust the understood object. Before objectification there is a smooth process, there is the world of life, which is the presupposition of objectification.

From existentialism to hermeneutics

No less and even more vigorously than Husserl, M. Heidegger polemicizes with objective and calculating thinking. In Being and Time, he shows how conceptual abstractions presuppose lived experiences, of which those abstractions are the no longer living derivatives. The second phase of his philosophy is also characterized by the polemic against objectivist thinking (metaphysics and the scientific spirit).

At the center of his reflection, there is no longer that particular entity that is man, but rather the Being. Now, this Being is far from identifying itself with the most real being, because it is fluidity and temporalization, manifestation and concealment: it is the possible Being, its infinite possibilities, which have manifested, which have not manifested, or which will be able to manifest, and it is therefore by eminence never totally present, never circumscribable. The possible is therefore superior to the real and includes it. In both phases of his thought we, therefore, have a rigorously finite position, where man tends towards the Being, or, inauthentically, distances himself from it, and a rigorous anti-rationalism: discursive thought does not bring us closer to it but distances us from the Being, towards which tend instead poets, or rather some poets, and the wisdom placed in certain ‘original’ words.

The finalistic approach is also at the basis of hermeneutical philosophy (H.G. Gadamer), of evident and confessed Heideggerian inspiration. Before understanding, it reflects on the understanding, on the conditions of understanding, and finds that understanding is interpreting, and is therefore conditioned by the situation of the interpreter. But if everything is interpretation nothing is indisputable, everything is subject to revision. The intent of hermeneutic philosophy is, once again, anti-objectivist: it denies absolute transparencies. The humble listening and not the superb seeing is the appropriate metaphor of thinking.

Philosophy as clarification and analysis

The ancient idea of philosophy as analysis and as the liberator from factors of conceptual confusion can be found in analytical philosophy. This idea is for example expressed by B. Russell when he affirms that only through rigorous methods of analysis it is possible to purify and transform, and thereby make correct and fruitful, otherwise vague and approximate notions and sources of errors such as intellect, matter, consciousness, knowledge, experience, causality, will, time.

For his part, L. Wittgenstein states in the Tractatus: «The aim of philosophy is the logical clarification of thought. Philosophy is not a doctrine, but an activity. A philosophical work consists essentially of elucidations. The fruit of philosophy is not philosophical propositions, but the clarification of propositions». In the second phase of his thought Wittgenstein speaks of a plurality of languages, correlatives of as many ‘forms of life’, i.e. cultural contexts within which those languages are intelligible (and with this a Hegelian, as well as hermeneutics, the movement seems to emerge).

R. Carnap observes that metaphysical problems are pseudo-problems and the correlative propositions are pseudo-propositions; therefore, a purification must be made to eliminate non-scientific elements from philosophy, and with this, the logic of science will take the place «of that inextricable tangle of problems which is known under the name of philosophy». A.J. Ayer likewise says that the philosopher must not seek out primary principles, nor make judgments a priori about the validity of our empirical beliefs, but limit himself to works of clarification and analysis.

The current debate

A renewed way of understanding cognitive activity (including science) in relation to history and with an alternative interpretative dimension to the traditional attempts at the normative foundation has transversally affected both philosophical areas in which it is now customary to distinguish philosophical, analytical and continental reflection, with the first label referring to the whole Anglo-American philosophical production, traditionally characterized by a linguistic approach to philosophical themes, and the second label referring to European production which, to a large extent, is recognized in hermeneutical philosophy.

The recognition of the impossibility of maintaining the concept of truth as the acquisition of objective knowledge, independent of cultural presuppositions, social contexts, and historical changes, has directly or indirectly marked much of the philosophical debate. There has been a vast convergence, though respecting the different approaches inspired by different philosophical traditions, on the impossibility of achieving, in the scientific, ethical or aesthetic field, certainties that are definitive, immutable and independent from history. This has had wide and profound repercussions on the very identity of philosophy.

Tibetan philosophy

Tibetan philosophy developed from the texts and assumptions of Indian Buddhism and almost exclusively in the Buddhist sphere, offering interesting solutions and developments to the Madhyamaka, Pramāṇavāda and, to a lesser extent, Yogācāra currents. Some key concepts used by contemporary interpreters of Indian and Buddhist philosophy, such as the distinction between a *svātantrika and a *prāsaṅgika current in Madhyamaka, and the notion of «root text» (mūla) of a certain school, dating back to Tibetan scholasticism. In the self-representation of their own tradition, Tibetan thinkers give a decisive role to the debate held in bSam yas towards the end of the 8th century, during which it was decided what form of Buddhism to adopt in Tibet. In opposition, there were the gradualist current, of Indian origin, linked to Śāntarakṣita and Kamalaśīla (Madhyamaka) and which was the winner of the debate, and an instantaneist one, of Chinese origin and linked to Chan Buddhism. Instantaneism then remained a constant key of interpretation and was applied to various forms, always minor, of Tibetan Buddhism.

The idea that no practice was needed to achieve awakening (bodhi) was proposed to bSam yas, since Buddha’s nature is already present ab initio in everyone and it is only necessary to realize it through a form of intuitive anagnosis. On a more properly philosophical level, central to Tibetan philosophy is the debate among the supporters of «emptiness in itself» and «emptiness of what is other» (śūnyatā). Three of the four major Tibetan religious schools, the Sa skya, the bKa’ brgyud and the rNying ma, adhere to the Madhyamaka interpretation called «emptiness of what is other», which maintains that the absolute is devoid of all conceptual and dependent superimpositions, and therefore «empty» with respect to these, but not empty in itself. Nāgarjuna’s writings – according to this interpretation – would deny any reality at the level of conventional reality (saṃvr̥ti-satya), but not at that of absolute reality (paramārtha-satya). This would consist of knowledge (in Tibetan ye shes) that goes beyond the distinction between subject and object and is identifiable with the nature of the Buddha beyond its historical manifestation. This interpretation is decisively opposed by the dGe lugs school, from whose ranks come the great thinker Tsong kha pa (1357-1419), who accused supporters of the «emptiness of what is other» of turning Buddhism into a substantialist philosophy.

Tsong kha pa, therefore, adheres to Candrakīrti and the Madhyamaka current *prāsaṅgika. However, Tsong kha pa himself opposes Pa tshab and his disciples, who, following the current *prāsaṅgika, deny any proposition of Nāgārjuna’s tetralemma claiming that everything neither «exists», nor «does not exist», nor «exists and does not exist». This representation, according to Tsong kha pa, is self-contradictory and does not explain what is learned by the means of valid knowledge (pramāṇa). If, in fact, each object is ultimately empty and illusory, there is no distinction between the content of correct knowledge and that of an error, that is, between a vase and a piece of nacre that is mistaken for silver. In order to avoid such consequences, Tsong kha pa specifies the first two propositions of the tetralemma, which therefore states that everything neither «exists from the point of view of absolute reality» nor «does not exist from the point of view of conventional reality».

In Tibetan monastic universities the cursus studiorum is composed of epistemology (pramāṇa), Prajñāpāramitā, Madhyamaka, Vinaya, and Abhidharma (Theravāda). For epistemology, Tibetan philosophy develops its own literature, called bDus grwa, while the last five topics are studied on the basis of Indian texts, but through manuals based on the terminology of the bDus grwa. This develops discussions about vyāpti (anumāna), denial and classifications of correct or erroneous knowledge based on a Sautrāntika ontology as represented in Dharmakīrti. Constant is the attention to produce formally correct definitions and their use in debates. Especially in its beginnings, connected to the figure of Phya pa (1109-1169), the bDus grwa elaborates areas of investigation separate from those dealt with in India, while Sa skya Paṇḍita (1182-1251), one of the most important thinkers of Tibetan philosophy, strives to bring epistemology within the mark of Dharmakīrti. Developed in Tibetan philosophy is also the theory of apoha.

Arabic philosophy

One can speak of Arabic philosophy with regard to historical phenomena that occurred in different cultural and religious spheres, which also differed according to the historical period and the geographical area in which they were located, but which are basically united by the use of the same language: Arabic. The term includes both the so-called Islamic or Arabic-Islamic philosophy, which originated in the medieval Near East of the Muslim religion, and the so-called Arabic-Christian philosophy, which adopted Arabic as a language of expression following its close contacts with the Islamic world, together with the traditional language of the Christian Near East: Syriac. These two phenomena were followed by a third, represented by the so-called Judeo-Arabic philosophy; the latter, however, is better included within the sphere of Jewish philosophy.

Arab-Christian philosophy

Also including the philosophy that should be more properly defined as Syriac, the Arab-Christian philosophy comes to be placed in the Mesopotamian area (Syria, Iraq) in the 6th-13th centuries. The authors who were part of it all shared their belonging to two Christian sects, present in that area during the Middle Ages, but on two diametrically opposed theological positions: the Jacobite Church and the Nestorian Church, one of which made the divine nature of Jesus Christ prevail, and the other his human nature. To the formerly belonged philosophers who expressed themselves mainly in the Syriac language, and who dedicated themselves above all to questions of logical and metaphysical-theological nature, that touched on the fundamental themes of their religion: among them, we can remember Sergius of Rēsh ‛ainā (d. 536), the commentators on Aristotelian logic active around 700 (Athanasius of Balad, George Bishop of the Arabs), and the theologians James of Edessa (d. 708), Moses bar Kēfā (d. 903) and John of Dara (9th century); in the 13th century the two monophysite authors Jacob bar Shakkō (d. 1241) and more importantly Gregory Bar Hebraeus (1225-1286), the greatest representative of this philosophy, wrote various philosophical-scientific encyclopedias.

In the 9th-10th centuries some of these philosophers, who worked in Baghdad, continued the work of their predecessors, though expressing themselves in Arabic: this is the case of Yahyā Ibn ‛Adī (d. 974) and Abū ‛Ālī Ibn Zur‛a (943-1008). On the other hand, there were authors belonging to the Nestorian Church who, starting from the 9th century, mainly translated philosophical and scientific texts from Greek to Syriac and from Syriac to Arabic, on behalf of Muslim readers: among them, Hunain Ibn Ishāq and his disciples, active in Baghdad between about 850 and 910, need to be mentioned.

Arab-Islamic philosophy

The phenomenon of translations represented an important starting point for the development of Arab-Islamic philosophy: it was precisely on texts of Greek philosophy and science (especially the works of Aristotle and his commentators, but also writings of Hippocrates and Galen, Ptolemy and Euclid, and at least some of Plato’s works and the main authors of the Neoplatonic school: Plotinus, Porphyry and Proclus), translated into Arabic by Christian authors between about 800 and 1000, that the Muslim philosophers of the Middle Ages laid the foundations of their autonomous thought. Arab-Islamic philosophy began in Iraq, and in particular in Baghdad, during the first half of the 9th century, and from there it spread over the following three centuries – which represented the moment of its maximum development – first in Iran, and later in other neighboring countries, going as far as North Africa; to characterize it was mainly the need to harmonize philosophy as a rational study of reality with the contents of the Islamic religious tradition. The first manifestation of an Arab-Islamic philosophy took place with the Iraqi al-Kindī, known as the «philosopher of the Arabs» par excellence. He devoted himself to the organization of a series of paraphrastic-interpretative translations into Arabic and produced, among other things, fundamental sources of medieval Neo-Platonic philosophy such as the Ūtūlūğīyā (Theology) of the pseudo-Aristotle and the Kalām fī mahd al-khā’ir («Discourse on the Pure Good», better known as Liber de causis), as well as Arabic versions of a series of Greek writings by Alexander of Aphrodisiah or to him attributed. He himself, being basically a Neoplatonist, was also interested in aspects of Aristotelian metaphysics: an interest that he revealed in his main philosophical work, al-Falsafa al-ūlā («First philosophy»).

In his numerous philosophical writings, he touched on themes of metaphysical, physical, psychological (he was the first to introduce into Arab philosophy the question of the nature of human intellect in his Risāla fī l-‘aql, «Epistle on the intellect») and ethical (inspired by the stoic ideal of apathy); he also wrote a terminological dictionary, which laid the foundations for the thought of his successors. One can also speak of Neoplatonism in the case of two other important authors of the Arab-Islamic medieval philosophy of the first half of the 10th century. Abū Bakr al-Rāzī was mainly a doctor, but he also devoted himself to philosophy, developing themes and doctrines inspired by Platonism and Pythagoreanism, with fundamentally anti-Aristotelian positions (he was among the first, in medieval philosophy, to deny the Aristotelian concepts of finite space and time); he was, on the whole, a rationalism not devoid of elements taken from non-Islamic religions (Mazdeism, Manichaeism, Buddhism, and Hinduism), which brought him into conflict with some aspects of Islam and led to the destruction of many of his works. The Rasā’il Ikhwān al-safā’ («Epistles of the Brethren of Purity»), a philosophical-scientific encyclopedia in 52 treatises, was undoubtedly oriented towards Neo-Platonism, probably assumed through the interpretation given by the Islamic sect of the Ismailis; it is thought that the anonymous author can be identified with the Spanish Muslim Abū l-Qāsim Maslama al-Maǵrīṭī, editor of esoteric writing, Ġāyat al-ḥakīm («The aim of the wise»).

At the same time as Neo-Platonism, an Aristotelianism developed in the Islamic world, based on the commentary on the Stagirite’s writings: a commentary that, among the many exponents of this Aristotelianism, took on the character of an interpretative summary, or a paraphrase adapted to the needs of the reader, or a precise literal commentary of the text (reported entirely in Arabic translation), or even a philosophical encyclopedia. The first commentator, called the «second master» after Aristotle, was al-Fārā’bī. His epitomes of Aristotle’s logic had a considerable influence on medieval Arab-Islamic and Jewish philosophy; his famous epistemological treatise, Ihsā’ al-‘ulūm («The enumeration of the sciences»), followed an original scheme, which connected Aristotle to the Islamic religious sciences; his treatise on the intellect reanalyzed and developed the analogous work of al-Kindī. He was still also known for his ethical-political works, among which al-Madīna al-fādila («The virtuous city») stands out: in this work, he started from a brief exposition of theology, metaphysics, physics, and human psychology, to then explain his own idea of the ideal state, governed by an imā’m with the assistance of a senate of philosophers. A rationalist philosopher even in his approach to the Islamic religion, al-Fārā’bī created a school in Baghdad that continued to deepen and perfect his thinking until the middle of the 11th century.

The so-called «New Aristotle» was the most successful medieval philosopher in the Arab-Islamic world: Avicenna. Originally known as al-Fārā’bī from Central Asia and as a very fertile author (he was famous in the Islamic world as a mystic, and also in the Latin world as a doctor), in his numerous philosophical works he treated the contents of the logical, physical and metaphysical writings of the Stagirite in a systematic way, building encyclopedias in which he adapted the thought of the Greek philosopher to his own needs and his own religion, in an attempt to reconcile the Aristotelian tradition and the doctrines of Islam: an attempt that did not exclude new proposals on issues such as the nature of the human soul, or that of time and space. His two best-known and most popular philosophical encyclopedias in the Middle Ages, al-Šifā’ («The Cure», in 10 volumes) and al-Nağāt («The salvation», in three parts), were part of this purpose, which he followed in other writings; among them, we should remember al-Falsafa al-mašrīqīya («The oriental philosophy»), where philosophy was not based so much on rational and syllogistic concepts (according to the Aristotelian scheme) as it was on intuitive ones. Avicenna didn’t leave behind a simple school, but a true and proper orientation of thought, which found many supporters in the following centuries, but also several opponents.

This ‘Avicennism’ was based on an interpretation of Avicenna as the creator of an innovative Aristotelianism (this category included the Jewish philosopher converted to Islam Abū l-Barakāt al-Baghdādī, d. 1164), and assumed the characters of «Illuminationism», i.e. neo-Platonizing theosophy where Avicenna’s thought was altered and adapted (this is the case of authors such as Sihāb al-dīn al-Suhrawardī, d. 1191). Avicennism, which seemed in many ways in contrast with the theological doctrine of Sunni Islam, provoked within the latter the defense of the official Ashʿari theology, represented in the 11th century by its greatest exponent, the Persian al-Ġāzālī. He, after having studied at length the thought of Avicenna, exposed and refuted it in a sort of trilogy of a philosophical and theological character. In the first of the three works, Mi’yār al-‘ilm («The Criterion of Knowledge»), he expounded Aristotle’s logic, adapting its contents to the needs of Islamic theology; in the second, Maqāsid al-falāsifa («The Aims of the Philosophers»), he summarized the contents of the logic, physics, and metaphysics of Avicenna’s Daneš nameh («The Book of Knowledge»), to criticize them; this criticism, which aimed to find the irrationality of twenty points of Avicenna’s physics and metaphysics, was carried out in the third work, Tahāfut al-falāsifa («The Incoherence of the Philosophers»).

In the wake of al-Ġāzālī followed a Persian theologian and philosopher, Fakhr al-dīn al-Rāzī. In the 12th century, the Arab-Islamic philosophy that was founded, like that of al-Fārā’bī and Avicenna, on the interpretation of Aristotle’s thought, had a surprising, though ephemeral, development in Muslim Spain (today’s Andalusia) and in the nearby Maghreb; thanks to this development, that philosophy exerted a considerable influence not so much on Islamic thought in general as on medieval Jewish philosophy and Latin scholasticism. It was represented by three authors. Ibn Bā’ggia (d. 1138-1139) was, first of all, a commentator (his commentaries on Aristotle’s logic, physics and psychology remain, systematic and rationally ordered), but he was also the author of original philosophical writings: the best known was Tadbīr al-mutawahhid («The rule of the solitary»), that developed a theme already present in al-Fārā’bī by describing the ethical and intellectual characteristics of the ideal philosopher. Ibn Ṭufàil (1110 – 1185), perhaps a pupil of Ibn Bā’ggia, substantially deepened the idea of the latter, presenting in his philosophical work Hayy ibn Yaqzān («The living son of the vigilant») a theme partially mentioned in some of Avicenna’s writings, but which he approached differently.

The ideal image that Ibn Ṭufàil presented here was that of a man who, left alone with himself from birth, is able to develop his own philosophy, fundamentally Aristotelian in character, which then when he confronts with others, proves to have reached substantially the same conclusions as revealed religion. Averroes, a philosopher, and doctor as well as a judge, represented the best-known Arab-Islamic thinker in the Jewish and Christian West, thanks to the medieval and Renaissance translations, in Hebrew and Latin, of many of his works, at the origin of the development of ‘Averroism’. He became especially famous as a commentator on almost all of Aristotle’s work, to which he dedicated, between around 1160 and 1195, commentaries that were wither summarizing (the Epitomes), paraphrasing (the Middle Commentary), or literal (the Long Commentary). On many points he was in contrast with the interpretations of these works given by the Arab authors before him: he wanted to return, in logic as in physics and metaphysics, to the true Aristotle, intending to free him from medieval interpretations and instead willingly accept some of the interpretations given by Greek commentators (from Alexander of Aphrodisiah onwards).

Moreover, Averroes did not avoid tackling, particularly in his Fasl al-maqāl («The Decisive Treatise»), the difficult question of the relationship between Aristotelian philosophy and the Islamic religion, formulating a doctrine which, though being often erroneously defined «of double truth», was instead based on the idea that philosophy and religion, if correctly interpreted, will reach substantially the same conclusions. Islamic philosophy did not end with Averroes, even if its developments remained relatively unknown. Between around 1200 and 1800, there were several authors who, in different ways, should be ascribed to it. Among them, we can mention: the Spanish Ibn Sab ̔ī ΄n (1217-1270), who explored themes of Averroes’s thought in a rationalistic key; ‛Abd al-Latīf al-Baghdādī (d. 1231), who returned to the Neoplatonism of al-Kindī; the Persian Nāṣir al-dīn al-Ṭūsī (1201-1274), who was among other things a commentator of Avicenna; the Tunisian Ibn Khaldū΄n (1332-1406), the first historical philosopher of the Arab world; the Persian Mūllā Sadrā Širazī (1571/1572-1640), who was the protagonist of a revival of interest in medieval Arab-Islamic philosophy in Safavid Persia. It seems more difficult to talk about a real Arab-Islamic philosophy in the contemporary age, from the beginning of the 19th century onwards. With the disappearance of the points of reference represented by traditional authors, tendencies of thought have arisen in the Arab world, during the 20th century, which was fundamentally interested in the purely political problems of Islamic nations: Arab nationalism, Arab socialism. Islam has continued to represent an essential fact in Arab countries; but it has tended to be in opposition to the modern idea of philosophy as a secular discipline, freed from relations with religion: an idea that has not established itself much in the Arab world.

Christian philosophy

Christian philosophy is also interwoven with religious and theological themes: it can’t indeed separate itself from the so-called “revealed truths,” and therefore from the faith, and it has its true subject in God, within whom exclusively the world and the self can be understood, as the creature is understood in the creator, the finite in the infinite. Hence the different positions on the duties and the limits of philosophy, but always within the premise of its symbiosis with the contents of the revelation.

Augustine talks about the unity of faith and reason and of their necessary complementarity. Faith is the prerequisite to rational examination: you need to believe in order to understand, and even rational examination, the act of knowing, answers to God’s command. From this perspective, knowledge itself is not a simple logical exercise, but it is the search of truth made possible by constant divine assistance that “illuminates” the human mind. Hence the lack of distinction between philosophy and reflection on the dogmas of faith: the intellect continues and enhances the first and fundamental religious experience and pulls towards the beatific vision which will be the full contemplation of truth (that is God).

Medieval speculation followed this mentality before the rediscovery of Aristotelian philosophy, which radically changes the context of medieval philosophy. It is at this point that we find the definition of natural philosophy and reason, extraneous in their nature to Christian tradition and reason, and the problem of their relationship to theology, that is to Christian speculation, arises. Thomas Aquinas will make the most notable and coherent effort of welcoming Aristotle’s philosophy within theological speculation, after distinguishing the two.

The reason is autonomous and it can ascend from tangible reality to higher forms of reality, up to the existence of God, which it can prove, as it can prove some of its attributes. Beyond reason, there are some unprovable truths such as the Trinity, the creation in time, the incarnation, the original sin. But the fact that they lie beyond reason does not mean they are irrational: instead, reason has the function of preparing us to accept these truths, because they do not go against reason, compared to which they are instead probable (or non-contradictory).

Jewish philosophy

We define as Jewish philosophy the philosophical ideas of those authors who lived in various geographical regions (in the Near and Middle East, in Europe and northern Africa) after the 1st century AD, who used different languages as a means of expression but who were united by two common characteristics: their Jewish ethnicity and their more or less formal adherence to Judaism – two aspects which, in the traditional view of the history of the Jewish people, would essentially coincide. Often, but not always, the various means of linguistic expression of this philosophy coincided with the most important languages of the areas wherein it operated. During the 1st century, Jewish philosophers wrote in Greek, the academic language of the Near East at the time.

During the 9th-12th centuries, when they were primarily active in northern Africa and Muslim Spain, they wrote in Arabic (or more precisely, in the Jewish version of this language, Judeo-Arabic), and Jewish thinkers continued to write in this language for the following period (13th-16th century) in some Islamic countries south of the Mediterranean.

Between the 13th and 18th centuries, Jewish philosophers who worked in western European countries created their own literary language, medieval Hebrew, which emulated and counterposed first the medieval and renaissance Latin of the contemporary Christian Scholasticism, and then the languages who had started to spread in the gentile European culture of the time.

Finally, in the 19th-20th centuries, and more specifically after 1850, with the rise of the Wissenschaft des Judentums («science of Judaism») and the progressive assimilation of Jewish people within European societies, there was a linguistic fragmentation: Jewish philosophers expressed themselves in the literary language of the place where they lived (English, French, German, Italian); only in eastern European countries, where there was still a neat separation between Jewish communities and the local nationalities, Jewish thinkers still expressed themselves in Hebrew, or at the very least they adopted as a means of expression the language spoken by their communities: Yiddish. In general, not only from a linguistic standpoint but more importantly in regards to the methods and even a good portion of the contents, Jewish philosophy seemed characterized by a notable ability to adapt and absorb the various cultures among which it existed, both Islamic and Christian, thus creating a Jewish version of the most important gentile philosophical and theological schools it was in contact with.

Connections to Greek and Arabic philosophies

The first version of ‘Jewish Platonism’ can be found around 40 AD, in Egypt; its representative was Philo of Alexandria. He published in a series of works, all initially redacted into Greek, his substantial adhesion to various philosophical doctrines of Plato and of the platonic school of his times, attempting to applying them to his interpretation of the Old Testament; in doing so, he focused mostly on the allegorical-philosophical reading of the first chapter of the genesis, dedicated to the creation of the world. Nonetheless, Philo’s case remained essentially isolated. It was only a few centuries later that a wider return of an interest in Greek philosophy occurred for Jewish thinkers: an interest that was now mediated by the linguistic and conceptual interpretation carried out by the medieval Arab-Islamic philosophy. To jumpstart this interest was the rise of the ‘Jewish kalām’, an apologetic theology towards Judaism in its two then prevalent versions (Rabbinic and Karaite), inspired, in some aspects of its contents and form, to the contemporary Islamic apologetic theology.

The most renowned representative of this school of thought, Saadia Gaon (882-942), active in Egypt and Mesopotamia, introduced some elements of the Neoplatonism of the Arab-Islamic philosopher al-Kindī, and in general some methods and doctrines of Islamic theology, in his main work, the Kitāb al-amānāt wa-l-i’tiqādāt («Book of Beliefs and Opinions»). However, it was with his contemporary and compatriot Isaac Israeli (850-950) that a true Jewish philosophy in Arabic was born, which systematically reproduced the structures and a good portion of the contents of al-Kindī’s philosophy and the works connected to it (the Ūtūlūğīyā «Theology» of the pseudo-Aristotle and the Kalām fī mahd al-khā‛ir «Liber de causis»), adapting them, where necessary, to the doctrinal needs of Judaism.

Jewish philosophy in Muslim Spain. This Jewish Neoplatonism found an ulterior and wider development in the Muslim Spain of the 11th-12th centuries. Between 1040 and 1080 ca., in this area, the works of two authors with opposing ideas were composed: Shelomoh Ibn Gabirol (1020-1070 ca.) and Bahyā Ibn Pāqūdā (second half of the 11th century). The former, in his metaphysical work Yanbū‛ al-hayāt («The source of life»), offered for the first time an original interpretation of the Arab-Islamic Neoplatonism; the latter, in his mystic-ascetic work Farā’id al-qulūb («The duties of the hearts»), attempted to conform the structures and the contents of Islamic mysticism to the needs of Judaism, thus achieving a sort of ‘Jewish Sufism.’

An even bigger development of Jewish Neoplatonism in Spain can be found between 1120 and 1140: in this time, in the Iberic peninsula, the most important works of the Judeo-Arabic authors belonging to this school of thought were written, such as the Maqāla al-hadīqa («The treatise of the garden») by Mosheh Ibn ‛Ezrā (1055-1138 ca.), the Kitāb al-‛ālam al-saġīr («Book of the microcosm») by Yosef Ibn Zaddiq (died in 1149), and the Kitāb al-Khazarī («Book of the Kuzari») by Yĕhūdāh ha-Lēwī (1075 ca. – 1141). These three works had in common their focus on treating philosophical and theological questions by taking inspiration from Arab-Islamic authors who belonged not only to Neoplatonism (the Rasā’il Ikhwān al-safā’, «Encyclopaedia of the Brethren of purity») but also to Aristotelianism (al-Fārābī, Avicenna, Ibn Bāggia). This Jewish Neo-Platonism, open to a confrontation with some aspects of Aristotelianism, continued even after 1150 in other geographical areas (Morocco, Tunisia, Egypt), and especially in Yemen; in this last region a sort of ‘Jewish Ismailism’ developed in the 12th-16th centuries, which shared with true Ismailism the interest for the theological-philosophical doctrines of Avicenna, adapting it to its own religious needs.

Jewish Aristotelianism

In the second half of the 12th century, on the other hand, the important phenomenon of Jewish Aristotelianism arose, autonomous from Neoplatonism and in contrast to some aspects of it. It was represented by two Arabic-speaking Jewish authors: Abraham Ibn Dawūd (also known as Johannes Avendaut), active in Toledo as a philosopher of Avicennan orientation and a probable collaborator of the philosophical translation from Arabic to Latin of writings by Avicenna, and especially Mōsheh Ibn Maymūn, known as Maimonides and active in Cairo as a doctor, jurist, and philosopher. The latter, certainly the best-known representative of Jewish philosophy, offered in his greatest work, the Dalālat al-hā’irīn (The guide of the perplexed), an Aristotelian interpretation, based mainly on the works of al-Fārābī and Ibn Bāggia, of the main elements of the Jewish religious tradition, in an effort to rationally explain the contents of the latter. At the same time as Ibn Dā’ūd and Maimonides, a Jewish philosophy developed in Spain and Western Europe during the 12th century in a language that was no longer Arabic, but Hebrew. Its founders were Abraham bar Ḥiyyā (c. 1065-1136), an Aragonese Jew interested in Greek science and philosophy and in contact with both the Muslim and Christian worlds, and Abraham Ibn ‛Ezra (1089-1164), a Spanish-Jewish eclectic writer, active as an astronomer and exegete of the Bible in Italy, France and England after 1140.

Writing for readers who were unfamiliar with the Arabic language, these authors had to create the Hebrew language that was new in many aspects, capable of expressing the fundamental concepts of Arabic philosophical and scientific thought: medieval Hebrew. After them, many other Jewish authors who wrote philosophical works in Hebrew were active in Spain, Provence, and Italy between 1200 and 1500. These works, still under study today, reflected Jewish interpretations and adaptations of different aspects of Arab-Islamic thought first (at least until 1350), and of Latin scholasticism later (especially from the 14th century). It is possible, for some of them, to speak of ‘Jewish Averroism’: risen from an attempt to match Maimonides’ thought with that of Averroes, this Averroism was developed by several authors in the geographical areas and periods mentioned above, and found its most famous and brilliant expression, not without innovative aspects, in the Provençal Jewish philosopher and scientist Lēwī ben Gērĕshōn, known as Gersonides (1288-1344). Two other phenomena were present alongside this: a ‘Jewish Avicennism’, which developed in the Spanish and Provençal area between about 1250 and 1400; and a sort of ‘Jewish scholasticism’, which developed in Italy around the beginning of the 14th century and was revived there and in Aragon in the second half of the 15th century. The latter was born from the attempt to interpret and adapt to Jewish tradition the main aspects of different schools of Latin Christian thought of the time: Thomism, Scotism, Nominalism.

Jewish enlightenment

The line drawn by medieval Hebrew philosophy continued in Europe, along lines that still had to be clarified in the followed method and content, after 1500, assimilating aspects of the non-Jewish thought of the 16th-18th centuries: its last original manifestation was the Haskalah, known as ‘Jewish Enlightenment’ and developed in the Dutch and German areas after 1750. However, in the second half of the 19th century, with the assimilation of a large part of European Jews into non-Jewish European society, Jewish philosophy fragmented not only from a linguistic point of view but also from a religious point of view, maintaining only a generic cultural and national identity. In this case, it is still difficult to speak of a truly unified Jewish philosophy: one can perhaps speak of different authors of Jewish culture, each of whom is part of one or another different aspect of contemporary European philosophy.

Chinese philosophy

Towards the end of the 19th century, the expression zhexue, borrowed from the Japanese language, was adopted in China to convey the term philosophy; an expression which literally means «knowledge to become a wise person» and which, in the Confucian perspective, should be understood as the wise man’s ability to deal with issues inherent to the human condition. In this sense, philosophy is a knowledge, a practical knowledge, not theoretical or speculative: if however, one wanted to find in China that same tendency to build imposing systems of thought, typical of the Western tradition, the idea of a Chinese philosophy would be not only problematic but also rather inadequate, as in China it was a completely different experience, not reducible or assimilable to already known thoughts and systems.

Thus, the idea of a history of Chinese philosophy is an obvious linguistic loan from the West, as it is in fact problematic, if not impossible, to write about it or deal with it in the recurrent or more familiar sense. Nevertheless, the need, felt in the course of the 20th century, to still write a history of Chinese thought or philosophy did not originate in China, but came, like other things, from the West; thus recourse was made to Western philosophical concepts and doctrines in order to interpret the meaning of the Chinese classics and therefore of the schools of thought. In fact, those Chinese scholars and philosophers who wrote about the history of philosophy also had a solid knowledge of Western philosophy, often gained abroad and considered an essential analytical tool. The three most authoritative examples of this trend are Hu Shi (1891-1962), Feng Youlan, and Lao Sze-kwang (prop. Lao Siguang, b. 1927).

Cosmological reflection

Although in some mythical Chinese representations of the world one can trace germinal elements of the subsequent philosophical-cosmological reflection, it was only in the very first perception of the Universe that the Chinese fixed an ordered system of correspondences, harmonious and necessary, between the human body, political body and celestial bodies or, more generally, between natural entities, Earth and Heaven. It is a correspondence that invests the whole, from small to large, often represented in numbers, in articulated parts of a whole, in species, etc.; it recurs in the classical texts of the Chinese tradition, where it is not infrequently referred even to ordinary moments of human life and continually recalled to guide, as if it were an imperative, the action of man, especially that of the sovereign: «He who governs – said Confucius – by means of his virtue can be compared to the pole-star, fixed in its place while all the lesser stars pay homage to it» (Lunyu, Dialogues, II, 1).

Moreover, the correspondence between man and the elements of the natural order was the subject of extensive discussion in some works of the Han era (3rd century B.C. – 3rd A.D.), such as for example, to mention just two, in the Huainanzi («Book of the Huainan Master») and in the Chunqiu fanlu («The Luxuriant Dew of the Spring and Autumn Annal»), attributed to Dong Zhongshu. Impressive, in fact, is the detailed correspondence, developed in the Huainanzi, between the four seasons, the five phases, the nine sections and the 366 days of the sky, on the one hand, and the four limbs, the five organs, the nine orifices and the 366 joints of the human body, on the other. It is precisely this profound correspondence between cosmos and man that prompted Dong Zhongshu to consider man as the superior being par excellence. Not only is the man in and of himself a microcosm, but every ordered form of his action bears the same disposition, manifests the same nature. Thus, the State in general, as the regulated and organized form of human life, and in particular the Imperial State and administration, are themselves microcosm and therefore in direct correspondence with the cosmos. Even this conception had antecedents in the Shang era (18th-11th century B.C.), but it reached its full formulation only during the Han Dynasty, precisely to legitimize its system and administrative functions. Offices and functions found a correspondence with the five directions of space, as we read in the Huainanzi, and more generally with the structure of cosmic space and time.

A further extension of this correspondence, which offered fixed models of relation, was that which correlated the territories of Earth with the celestial ones and then also with the units of the celestial administration. And indeed, since the Ming dynasty (1368-1644), almost every city or administrative unit had its patron deity, whose functions in the celestial administration corresponded exactly to those performed by the earthly magistrate. It is therefore evident that in this cosmos all the parts are, without any prescription and in a completely natural way, disposed to mutual reaction, remaining in a state of spontaneity and immediate sympathy. And within musical harmony, the Chinese found the most convincing empirical demonstration of the profound cosmic register. It is not surprising, then, that some series of numbers (five, eight and twelve) recurrent in cosmological doctrines partly refer to similar numerical series belonging to music (five notes, eight voices, etc.), nor that they have also been applied to other fields, such as meteorology and medicine and the art of good government; so that every entity or phenomenon of the natural order reacts with favor or adversity to the way it is exercised. Similarly, the Chinese character qi was also used to indicate the primordial substance of the cosmos, which forms solid bodies by aggregating, and the ephemeral ones by disintegrating.

Qi can also differentiate itself and become yin, yang, or one of the «five phases» (wu xing), thus facilitating bonds and mutual actions everywhere, because it can be both the material foundation of action and the action itself. Each process develops according to an active (yang) and latent (yin) movement of phases, as it appears in the slow but constant succession of the seasons of the year. Even in the most powerful condition of yang the yin bud is preserved, and vice versa. Thus, for example, an old man can be yang in relation to a woman, but at the same time yin in relation to a young man. A duality, that of yin-yang, which was soon assumed as a principle of classification, and applied to philosophy as much as to social relations, medicine, and more. However, it served above all to represent and explain the dynamism of certain recurring processes: the succession of the seasons, the natural cycle of human life, the rise and fall of the dynasties.

Change in the world and of the world is a complex of changes, better understood and described in detail as «five phases». Phases that are a process of mutual production: wood (mu) produces fire (huo), fire produces earth (tu), earth produces metal (jin), metal produces water (shui), water produces wood, etc. The identification, moreover, of each phase is not so much with the natural element materially given, or with its substance, but rather with its quality or with a certain kind of action or activity. This philosophy or thought of correspondence has for centuries provided ideas and concepts that were essential to the development of certain knowledge, even proto-scientific ones, such as astronomy, medicine, divination, alchemy, geomancy, etc. The Chinese doctrine of alchemy, for example, was generally based on ideas of correspondence between macrocosm and microcosm, and thus practitioners used to consider materials, tools, and even individual operations, as the vivid and perceptible expression of the microcosm, where every entity, every change and therefore every reaction was precisely similar to the work or daily processes of nature.

The analysis of human nature. The Chinese interest in human nature derived from the need to understand the intimate constitution of mankind, both to better orient its ethical-political conduct in the world and to specify its role and function in the order of the Universe. The Chinese term xing, often translated as «nature», derives from sheng (which means «life; to be born; to produce»); the term ren is equivalent to «human being» (or «human beings»), hence the habit of referring to «human nature» with the expression renxing or, more simply, xing. Human nature can be understood in a biological sense, as Yang Zhu does in the 4th century B.C., when he speaks of «keeping one’s life intact» (quan sheng) or «one’s nature»” (quan xing), referring to human health and longevity. Similarly, Gaozi, a contemporary of Mencius, seems to refer to xing taking into account the only sheng, that is, what perhaps gives life to human beings; for him, human nature is preserved in the individual through the instinct to feed, and over time through the innate tendency to reproduce.

In the Guanzi, a work whose main nucleus was formed around 250 B.C., sheng is the bodily activity of man, that is, the sensory and emotional life. But human nature can also be understood in a more limited sense, with reference only to man’s desires. Thus, in the 5th century B.C. Mozi, in dealing with the basic human constitution, often dwells only on certain desires, those of life, material well-being, and honors. Having received life as a gift from Heaven, men in their natural state are moved exclusively by their own desires, without caring for their fellow human beings or family members. A similar use is found, in the 4th-3rd century B.C., in Xunzi, though he sometimes seems to recognize a benevolent disposition for beings of his own kind in man, considered in his natural state. In the ethical inclinations shared by all men, one can also see the peculiarity of human nature; thus Mencius subtly argues about righteousness, the sense of justice (yi) that the human heart (xin) has in itself, putting this before the instinct to feed and reproduce, remarked instead by Gaozi. In this way, he opposes any idea of benefit, of advantage (li), as an effect of a selfish impulse, both in the sense of Yang Zhu, that is, of what is useful for the sole preservation of one’s own life or nature, and in the sense of Mozi, that is, of what is legitimate only after having benefited others. Mencius also considers human nature as a condition, a state that needs to be constantly cultivated and therefore developed. Moreover, in some texts, e.g. in Zhuangzi, a Taoist work of the 3rd-2nd century B.C., human nature, although not bearing any particular connotation or specificity, reveals one disposition of man, his spontaneity. In every circumstance, or event, or fact, man must react spontaneously, although doctrines or ethical principles do not fail to exert their influence.

The empty heart (xu), devoid of any preconception, will then be like the clear mirror or water that reflects everything without the slightest distortion. Thus man can restore his original natural state. From Mencius obviously originates the idea of human nature professed by the Confucians of the Song-Ming era (10th-17th century A.D.), such as Zhu Xi and Wang Yangming, who thought of the heart as the source of ethical inclinations and dispositions; if however, inclinations had to be continually cultivated in Mencius’ doctrine in order to develop ethical principles, these Confucians consider these principles as already active in the human heart. Therefore, man’s action must strive to restore the original state of the heart, so that both ethical principles and his behavior, in general, may manifest themselves naturally and without impediment. Various other and more eclectic conceptions of human nature have taken place over the centuries. There was, for example, that of some philosophers of the Han era who, well aware of the doctrines of Mencius and Xunzi, affirmed, respectively, the original goodness and wickedness of human nature.

Dong Zhongshu believes that there are seeds of both goodness and evil in human nature, and that man, like Heaven working through yang and yin, subordinating this to that, must, therefore, subject evil to good. Yang Xiong (active between the 1st-century B.C. and 1st-century A.D.) considers human nature as a mixture of goodness and evil; and Wang Chong, in the 1st century A.D., concludes that the diversity of humans expresses a diversity of nature and that the different idea of human nature of Mencius, Xunzi and Yang Xiong reveals precisely the variety of the human species. And other Confucian thinkers of the Tang (7th-10th century) and Song (10th-13th century) era also speak of various degrees of human nature. On the other hand, every conception of human nature is more or less intimately connected with the perception of the Universe. Mencius considers tian (the «Heaven») as a supreme entity, which originally gave the man a peculiar nature, already ethically predisposed and oriented. So man has nothing else to do but follow that orientation, visible sign of the celestial will: man serves Heaven, manifesting a wholly natural fidelity. Moreover, tian, as the supernal source of all richness and regularity of the natural order, entrusts to man, according to Xunzi, the continuation, and completion of his creative and life-giving work. A work which also affects the social life of man, since the norms which order and regulate his conduct are in truth also a human completion of the heavenly work. Both Cheng Yi and Zhu Xi, Confucians of the Song Age, also understand human nature from the metaphysics of the li («principle») and qi («vital energy» or «material energy»). In fact, man’s nature is good as a moral nature and it is so because of the action of li alone, but as a mixture of li and qi it can be as good as it is bad since the action of qi can differ qualitatively from man to man.

The doctrine of knowledge

The Chinese term xin can be translated as «mind» or «heart»: it is the guide of man, in the sense that it guides his action. Being in the world, xin receives solicitations from the world and thus guides man’s action, precisely by moving from those solicitations. The sensory organs operate in the world and, by distinguishing, they offer xin a distinct world: sweet and bitter, black or white, or red, etc. What matters is that the subject, man, is in the world and not in the mind and that the faculty of the senses or of xin is the ability to discriminate or discern one thing from another, the human being from another being, good from evil. Ultimately, xin exists in the world and acts in it with the peculiar disposition to distinguish, to appropriately divide the realities of the world, and thus to guide man’s action.

In China, as in Chinese philosophy itself, there has always been a profound sense of the reality of the world, which has led to almost shying away, over the centuries, from the inclination to skepticism; even when doubts have been raised about the reality of knowledge, none have ever come to reject its validity in its entirety, if not for the need to express and affirm higher degrees of knowledge. Moreover, the doctrine of knowledge has never been understood as separate, distinct from that of reality, and from a certain more common pragmatism. Instead, knowledge is part of reality itself, and therefore its doctrine is nothing more than a part of the doctrine of reality. Thus a significantly holistic idea of knowledge has been affirmed, in which even the investigation of the detail is never reduced to the knowledge of the detail itself, but serves, as the entire cognitive activity, to reveal the complex system of the densely woven relationships of the Universe.

Therefore, it is not just the knowledge of things, facts, processes, etc. of nature, but similarly of values, virtues, and above all of ultimate reality. Nor has the doctrine of knowledge ever been directly or exclusively linked to the development of science and technology, nor has it ever been considered a way to justify the present science or one of its expressions. It is well known that over time China developed an extraordinary empirical science and often prodigious techniques, which, however, never had a disruptive effect on the doctrine or philosophy of knowledge, as it instead happened in the West; and this was also because such philosophy is only a part, and certainly not the most important, of the complex of Chinese philosophies. Not having postulated systematic procedures, nor a universal method of knowing, Chinese philosophy has recognized a variety of ways to verify empirical knowledge of things and to classify what is derived from it. In Yijing and in some commentaries (zhuan) on this classical text – which already towards the end of the Western Zhou dynasty (11th – 8th century B.C.), or in the period of the Eastern Zhou dynasty (8th – 3rd B.C.), reached a form very similar to that later accepted – one finds the first formulation of the Chinese doctrine or philosophy of knowledge, based on a complete experience and observation of reality, be it the Universe or the small world of man. This knowledge ensures that man acts correctly and more importantly makes decisions in accordance with it.

To know means to observe everything in its entirety and it is an activity expressed by the Chinese term guan, the twentieth hexagram of the Yijing: it is an observation that sees things as they are in nature (big and small, far and near, etc.) and in particular their mutual relations in the total system of reality. It is through the senses that the true nature of things is revealed to man; the knowledge of the «ten thousand things» (wanwu) matures precisely from the observation of their multiple peculiarities. The modes of observation are many, and all possible since the mind is naturally in a state of «great pure enlightenment» (from Qingming). The mind is originally endowed with cognitive power, so much so that it orders and organizes the sensitive experience into the knowledge of things, hence ideas, concepts, and names of things themselves. That the knowledge of the world is right is ascertained by the correctness of man’s actions. By virtue of this, any knowledge can be rectified, moving from the effects of unrighteous actions. But the correctness of knowledge is also verified by the fact that it is the things themselves that manifest and make themselves known, thanks especially to a natural interaction between them and the human mind and body. The Chinese term xian, the thirty-first hexagram of Yijing, expresses this condition of mutual action, interaction, mutual knowledge. The complete observation of things and the natural and spontaneous interaction with them are for man a source of reflection and therefore of knowledge of his own nature and mind. It is direct knowledge and deeper experience of things and nature, which is not limited to a simple sensory experience. Reality and being are inseparable, necessarily interrelated, so much so that knowledge is never elevated to pure abstraction.

Since the time of Confucius the world of reality has been conceived as made up of Heaven, Earth, human beings, the multiplicity of things: all of them knowable according to their changes and natural interactions. All beings bear the power of change and this change, in turn, brings an intrinsic regularity. Well, man can come to understand this becoming, can actively interact in the world of reality, and therefore of human society, and contribute to its maintenance and harmony. In this context, Confucius deepens the theme of knowledge: knowing others (zhiren), knowing the mandate of Heaven (zhi tianming), etc. It is a knowledge that concerns both things in their concreteness – and therefore people, social norms and rules of conduct – and the profound nature and raison d’êtreof life and reality. Man can then know, have direct experience, act correctly for the perfection of his own nature, and for the harmony of the world. Observing and investigating the nature of things, and above all human affairs and the effects produced on the political and social level, is for man an experience both moral and historical. In fact, what man observes, investigates, and therefore knows is not something abstract, independent, detached from reality, but they are things, human beings, historical facts, world events related, and interacting with the man himself. If the original goodness of man’s nature descends from Heaven, and thus is its gift, as Mencius professes, then man must dedicate himself to the cultivation and development of that gift, living ethically.

To know therefore means to investigate and reflect on human nature, in order to reveal its intimate and potential moral disposition. Man thus also knows Heaven, the true and only source of his moral nature. And this, ultimately, is the deepest knowledge of reality. The mind, nature, and body of man are, according to Mencius, manifestations of “qi” («vital energy»), although distinct; just as, on the other hand, “qi” is the energy that creates and animates everything that exists between Heaven and Earth and is the vital and moral nature of the ultimate reality. One understands, then, why human nature and mind are full of “qi” and why the moral disposition is inherent in human nature. There is, then, an intimate commonality between man’s mind and the nature of Heaven, so much so that his being and that of the Universe are almost interchangeable. This is true harmony, true unity between man and Heaven, and therefore between men themselves, experienced through knowledge and identification with Heaven. In another perspective, Xunzi considers Heaven as a reality governed by its own regularity and laws, which acts independently from human will and intentions; so the wise man must not know Heaven, but reveal its regularity and deeper principles, especially to preserve and support the activity and development of man and society. This implies a knowledge of the succession of the seasons and of the action of the natural forces yin and yang. There is, therefore, no link between human action and Heaven, if anything, there is a radical separation. The human mind, according to Xunzi, is able to observe and experience the things of the world and, at the same time, to use their specificity to order and set the rules of a language, always with the aim of impressing a beneficial development to political and social life. This emerges very well from his doctrine of the «rectification of names» (zhengming) and «removal of obnubilation» (jie bi).

The human mind knows things and establishes concepts, ideas, both to describe them and to identify them. This process is not arbitrary or aprioristic, but it derives from the human experience itself of things in the world and the ability, always human, to organize, classify, and order this experience. The choice, then, of names is a conventional act, necessary to identify, signify, and indicate the things of the world. Nevertheless, it does not preclude human knowledge, although naming, using language, and knowing to happen at the same time. Xunzi’s exhortation to remove all obfuscation from the mind reveals how important it is to know the truth in its entirety. Often, according to him, man is dominated by a single idea, or a single thought, and thus loses the totality and expanse of truth. Knowing the whole truth is not, therefore, equivalent to the formulation of doctrine, but to the removal from the mind of all partiality of views, doctrines, or ideas. Finally, the Daxue («The Great Learning») and the Zhongyong («The doctrine of the mean»), two chapters of the Liji («Book of Rites»), one of the canonical texts, have certainly contributed to defining the doctrine or philosophy of knowledge, as developed in the tradition of classical Confucianism. In fact, the Daxue merely laconically emphasizes how much the perfection of one’s own nature depends on the investigation of things, and therefore on the growth of knowledge, while the Zhongyong, in turn, simply indicates to man the way that brings from the perception of reality and the feeling of sincerity (cheng) to the ultimate reality, as sincerity is the nature of truth, of reality, and therefore the way to Heaven that manifests itself in the nature of the wise, as an inclination to good and a moral intention.

Analytic philosophy

Current of thought developed mainly in England from the beginning of the 20th century, and aimed mainly at the study of language in its various aspects (scientific, daily, ethical, logical, etc.), favoring the analysis of specific problems over the elaboration of broad and comprehensive systems.

From the school of G.E. Moore to the Tractatus of L. Wittgenstein

Bringing the premises of traditional English empiricism to their final consequences, G.E. Moore founded a school in Cambridge, wherewith thirty years of teaching (1911-39) deeply influenced all English philosophy, a school destined to develop. The acceptance of a conscious realism leads Moore to assume as an essential task of a philosophy the clarification of the implicit assumptions, on the linguistic level, of common sense, in order to more rigorously guarantee the realistic assumptions (even if his method is composite and still suffers from psychological suggestions).

On the other hand, starting from mathematical investigations and taking cues from the work of G. Frege and G. Peano and from the mathematical teaching of A. Whitehead, without however neglecting theories such as those of A. Meinong on ‘objects’, B. Russell arrives at a logical and linguistic investigation of mathematical propositions, which leads on the one hand to the theory of defined descriptions, and on the other to the theory of types. L. Wittgenstein’s Tractatus logico-philosophicus (1922), in which the results and problems of both Frege’s and Russell’s researches converge, as well as the introduction of original logical techniques (propositional calculation using the matrix method), poses the need to formulate a philosophy of language in which traditional gnoseological, metaphysical and ethical problems are absorbed.

It is usual to trace back to philosophy the logical positivism that, by drawing inspiration from some statements of Tractatus, elaborates with M. Schlick the so-called principle of verification («The meaning of a proposition is the method of its empirical verification»), proposing a radical anti-metaphysical reductionism. The meeting of logical positivism and American pragmatic currents, following the emigration to the USA of most of the exponents of the neo positivist movement (such as R. Carnap, H. Reichenbach, C.G. Hempel), determines a confluence of interests and creates a mutual stimulus.

The most significant products can be considered W.V. Quine’s essays on ontological and semantic problems, N. Goodman’s research on phenomenal languages and inductive inference, H. Putnam’s studies on the problems of meaning, truth, and realism, and S. Kripke’s studies on modal logic and the reference of linguistic terms.

New hypotheses of language analysis

Meanwhile, in the second phase of his thinking, Wittgenstein, whose teaching at Cambridge (1929-47) had proved to be extremely fruitful, and had influenced the whole English cultural environment, turned his attention to language not so much in its structure as in the multiplicity and variety of its uses and functions, proposing the theory of linguistic games.

The Platonic-Aristotelian conception of language supported by Wittgenstein in the Tractatus and implying a mirroring language-reality correspondence is thus abandoned; the prerequisites for the construction of a rigorously formalized ideal language are dropped, as well as the model of reductionist analysis, and the investigation shifts to the problem of the different linguistic levels, the different roles of the various grammatical parts of discourse in various contexts, and the possibility of identifying varied syntaxes.

These theses are linked to the exponents of Oxonian philosophy whose most significant representatives, besides A.J.T.D. Wisdom, are G. Ryle, who links his analyses on the mind to behavioral cues, J.L. Austin, P.F. Strawson, who particularly develops the theme of the relationships between formal logic-informal logic and linguistic analysis, M. Dummett, who reformulates the ontological dispute between realism and idealism in terms of rival theories of meaning, and S. Toulmin, R.M. Hare and P.H. Nowell-Smith for ethical problems, preceded on this ground by the important study of the American C. Stevenson (Ethics and Language, 1944).

Starting from the second half of the 1960s, the perspective of analysis inaugurated by Austin with the posthumous How to do things with words (1962) has become increasingly more widespread in philosophy. This perspective conceives discourse as a set of linguistic acts characterized by their particular strength. Austin’s proposal of the concept of performative utterances, i.e. utterances that do not describe an act but serve to perform it, has been welcomed with interest. H.P. Grice’s work, who proposes a definition of meaning not related to words or phrases but to the ‘intentions’ of the speaker to produce effects on the audience, derives from the same perspective aimed at explaining language in pragmatic terms.

A systematic presentation of the concept of language and philosophical problems initiated by Austin can be found in J.R. Searle’s work, Speech acts (1969), where speech is presented as a form of behavior and its rules are fully described. In D. Davidson, perhaps the author who has enjoyed the greatest fortune since the 1970s, the study of meaning, in line with the positions of his master Quine (whose strict behaviorism he rejects, however), is above all equivalent to an empirical investigation of the statements believed to be true by the speakers of a community and the connections between these statements and the wider background of the speakers’ beliefs.

At the turn of the 20th and 21st centuries, perhaps the most important novelty is the attention to psychological and ‘mental’ issues. The interest in the philosophy of the mind (or philosophical psychology) is obviously not new in philosophy: it goes back at least to Ryle and Wittgenstein, who was however interested in depriving of any foundation, based on their linguistic analyses, the traditional mind-body dualism of Cartesian origin. Over the years, although the monistic orientation of the majority of analytical philosophers has not disappeared, more and more space has been given to the typically mental and psychological aspects that oversee the main human activities.

The study of the mental aspects related to meaning has had the effect of overlapping the investigations of the philosophy of language in the strict sense with those of philosophy of the mind, and particular emphasis has been acquired, in this area of intersection between the two sub-areas of philosophy, by the problem of intentionality, i.e. the tendency (theorized in the Middle Ages, but rediscovered by F. Brentano) of linguistic assertions and mental states to be typically addressed to extra-linguistic or extra-mental objects, so to have an intrinsic content (intentionality).

Intentionality is at the center of the attention of many analytical philosophers, from Searle and D.C. Dennett to J. Fodor, and it is probably the subject that reveals more than any other the broadening of philosophy’s interest in that type of psychological and mental questions, once considered to be only analyzable in exclusively linguistic terms.

Practical philosophy

This is a branch of philosophical sciences whose origins lay on the distinction theorized by Socrates and the Sophists and clarified in Plato, who generally divides science into πρακτική (referring to πρᾶξις, action), and γνωστική (referring to γνῶσις, knowledge), and more fully in Aristotle, who adds the poetic (ποιητική, referring to ποίησις, productive action) to the theoretical (ϑεωρητική) and practical sciences. The term “practical,” that post-Aristotelians substituted with “ethical,” can be found again in medieval and scholastic terminology.

In the Kantian system, which hinges on the dyad of theoretical reason and practical reason, the distinction between practice and ethics or morals becomes clearer, with the former concerning, in general, the world of action and the latter determining, within this world, the sphere of morally valid activity. This distinction, present again in post-Kantian philosophy, was nullified by the actualistic idealism of G. Gentile, who conceptualized theory itself as a praxis and denied the possibility of an autonomous practical philosophy. From the second half of the 20th century, the distinction was reintroduced and re-proposed by the main German schools of thought, on the basis of a renewed critical reflection on the themes of action and political rationality.

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