Illuminationist philosophy started in twelfth-century Persia, and has been an important force in Islamic, especially Persian, philosophy right up to the present day. It presents a critique of some of the leading ideas of Aristotelianism, as represented by the philosophy of Ibn Sina (Avicenna), and argues that many of the distinctions which are crucial to the character of that form of philosophy are misguided. Illuminationists develop a view of reality in accordance with which essence is more important than existence, and intuitive knowledge is more significant than scientific knowledge. They use the notion of light, as the name suggests, as a way of exploring the links between God, the Light of Lights, and his creation. The result is a view of the whole of reality as a continuum, with the physical world being an aspect of the divine. This sort of language proved to be very suggestive for mystical philosophers, and Illuminationism quickly became identified with Islamic mysticism.
Illuminationist philosophy stems from the Arabic term ishraq, meaning 'rising', in particular the 'rising of the sun'. The term is also linked to the Arabic for 'East', and has come to represent a specifically Eastern form of philosophical thought. It is used, especially within the context of Persian poetic literature, to represent a form of thought which contrasts with cognitive reason ('aql); that is, it is taken to be intuitive, immediate and atemporal knowledge. The source of this form of thought is often identified with Ibn Sina's 'Eastern Philosophy' (al-hikma al-mashriqiyya), a text about which there is a great deal of dispute and discussion, and which may never have actually existed. It is supposed to represent Ibn Sina's departure from Peripateticism and his attempt to construct a new and deeper philosophical system (see Islam, concept of philosophy in §2).
The real originator of illuminationist philosophy is al-Suhrawardi, a Persian philosopher of the twelfth century ad, who composed over fifty works but who is chiefly remembered for his brief Hikmat al-ishraq (The Philosophy of Illumination). In this book, al-Suhrawardi (in Persian, Sohravardi) adopts some of the main principles of Peripateticism (al-falsafa al-mashsha'iyya), but also sets out to challenge others. He criticizes Peripatetic approaches to a wide variety of topics, in particular quantification, the confusion between 'term' and 'utterance', the notion of amphiboly, petitio principii and many other issues (see Aristotelianism in Islamic philosophy). There is a marked similarity between his critique and that of William of Ockham, who also identifies in his Summa logicae what he regards as ten fallacies in Aristotelian logic. Both al-Suhrawardi and Ockham rearrange the parts of the Organon and omit from their discussions some of the books.
Illuminationist philosophy challenges the Peripatetic position of the absolute, unchanging and universal validity of the truths discoverable by Aristotelian methodology (see Peripatetics). It sets out instead to construct a system applicable to the whole continuum of being, including what is called 'immediate knowledge'. Al-Suhrawardi rejects Aristotle's theory of definition, arguing that there is no criterion for the parts of a definition (the genus and the differentia), and so the species is defined in terms of something less known than itself. He goes on to claim that some of the Aristotelian categories are superfluous, since action and passion are modes of motion, and possession and posture are kinds of relation. Thus we need only five categories instead of ten, leaving substance, quantity, quality, relation and motion.
The basis of al-Suhrawardi's approach is really Stoic and Megaric (see Stoicism; Megarian school). According to this approach, the denotation (the external object) should be compared with the thing, the sign should be compared with the utterance and what is signified should be compared with the meaning. These semantic notions are used to define the relation between the first atemporal act of thought and the second temporally-extended grasp of the thing known, its essence (Ziai 1990: 42-). This involves the development of a theory of types of signification, relation of class names to constituents of the class, types of inclusion of members in classes, and a well-defined theory of supposition.
In the illuminationist view of logic, a conclusion reached by using a formally established syllogism has no epistemological value as a starting point in philosophical construction. For a universal affirmative proposition to have philosophical value as a foundation of scientific knowledge, it must be 'necessary and always true'. Yet if we introduce the mode 'possibility' and give it an extension in time as in 'future possibility', the universal affirmative proposition cannot be 'necessarily true always'. This is because of the impossibility of knowing or deducing all possible future instances. The epistemological implication of this logical position is that formal validity ranks lower than the certitude obtained by the self-conscious subject who, when alerted to a future possible event through 'knowledge by presence', will simply 'know' it. The future event cannot be deduced at the present time and given universal validity (see Logic in Islamic philosophy).
The crucial notion for Illuminationist epistemology is knowledge-by-presence (al-'ilm al-huduri). This identifies an epistemological position prior to acquired or representational knowledge (al-'ilm al-husuli). This has often been related to intuitive knowledge, and results in attempts to unravel the mysteries of nature not through the principles of physics but through the metaphysical world and the realm of myths, dreams, fantasy and truths known through inspiration. The distinction between scientific knowledge and knowledge-by-presence is crucial for al-Suhrawardi, who claims that the essence of human beings lies in their self-awareness, through the luminosity of their own inner existence (see Epistemology in Islamic philosophy; Science in Islamic philosophy).
This approach also has implications for ontology. Illuminationism defends the 'primacy of quiddity'; it sets itself up against both Aristotle and Ibn Sina in upholding the priority of essence over existence. Some philosophers uphold the primacy of being or existence, and consider essence to be a derived mental concept, while those who adhere to the primacy of quiddity consider existence to be a derived mental concept. If existence has a reality outside the mind, then the real must consist of the principle of the reality of existence and the being of existence, which requires a referent outside the mind. Its referent outside the mind must also consist of two things, which can in turn be subdivided, and so on ad infinitum. That is, if 'existence' denotes an existent, then there must be another 'existence' connected to it which makes it real, and if so then this would also apply to the second 'existence', which leads to a vicious regress. To avoid this absurdity, we must regard existence as an abstract and derived mental concept; existence cannot signify an actual entity. If there were a distinction between a substance external to the mind and its existence, it would exist by accident, since two external substances must have different essences and cannot be distinguished by being existents. In that case, existence is nothing but a mental idea and cannot be defined. Since existence is attributable to many things, it must be mental (see Existence).
Illuminationism is distinguishable from Peripateticism through its semantics, logic, epistemology, ontology, the priority of the intuitive over the purely noetic, and also its use of a language of light entities to describe the whole continuum of reality. The latter consists of four things: intellect, soul, matter and a fourth realm named the 'alam al-khayal, which is similar to Platonic Forms except that entities in it are continuous with the whole of reality. This fourth realm (translated by Corbin as the 'mundus imaginalis' (Corbin 1971)) is describable as that of 'things as ideas' prior to taking on shape, that is, before they receive 'luminosity' from the One Source, the Light of Lights. The light received is essentially the same, and the luminous thing differs from other light entities only in respect of degrees of intensity. Luminosity flows eternally, and gives shape to the forms, thus making the entity 'visible' and known. The difference between things, then, lies not in their essences but in terms of the degrees of intensity of the shared essences of the things. All luminous things constitute an aggregate whole and are coeternal with the Light of Lights. The Light of Lights is one, but is neither beyond being nor nonbeing, nor does it have a will. Everything in the continuum is generated from the Light of Lights and shares a degree of light similarity. The Light of Lights is one with respect to all possible modes, known or discovered subsequently.
These highly suggestive references to light were taken up by a large number of later thinkers who developed it in different but connected ways. According to Nasafi, the existence of God is an infinite light, the existence of which is equivalent to its essence, and everything which exists is a face or expression of this light. God is the ultimate reality of everything which exists in the universe. Baba Afdal Kashani argues that the notion of being is more general than the notion of existence, since we can wonder whether a thing actually exists; being is then prior to existence, and experience of the light of God's creation is comprehended solely through an internal illumination of the soul. This results not in knowledge of a fact or thing, but rather in a way of relating to God, a way which maintains one's status as part of the deity. One of the key aspects of Illuminationism is its disinclination to make a sharp distinction between God and that which God has produced. This is what has made Illuminationist philosophy seem so close to mysticism at times, and it leads to a sharp differentiation from aspects of Ash'arite thought, such as adherence to the atom as the basic constituent of physical reality.
The influence of Illuminationist philosophy on the Islamic world persists to this day. A wide range of important thinkers including Nasir al-Din al-Tusi, Shams al-Din Shahrazuri, Sa'd Ibn Kammna, Qutb al-Din al-Shirazi, Jalal al-Din al-Dawani, the School of Isfahan and, right up to our own day, Ha'iri Yazdi, are clearly within this tradition of philosophy. When it comes to issues of interpretation, there is a controversy as to how close this form of philosophy really is to mysticism. Some writers such as Izutsu (1971), Rahman (1975) and Ziai (1990), stress its links with analytical thought and deny that there is anything particularly mystical about it. It is certainly true that the greatest interest has been focused on a relatively small number of al-Suhrawardi's works which have more of an esoteric nature, while his more technical and strictly logical works have tended to be ignored.
The work of Henry Corbin (1971) and Seyyed Hossein Nasr (1964), on the other hand, emphasizes the mystical contribution which Illuminationism makes, and they see the esoteric aspects of this form of thought as being of leading significance. There is no doubt that the general use to which Illuminationist philosophy has been put often involves mysticism, and there is little difficulty in combining it with the thought of Ibn al-'Arabi, for example, which later philosophers were to do. It is certainly true that some of the leading texts by al-Suhrawardi are entirely technical and deal with issues of philosophy which have no mystical dimensions, but it must be admitted that when one examines his general approach to metaphysics, it clearly fits in with many of the ideas which mystics like to use. The terminology of light points to a view of the nature of reality which is far removed from that presented by the Peripatetics, or even from Ibn Sina in his more suggestive and mystical moods. Illuminationism is not just a critique of Aristotle and Ibn Sina, but it is also the development of an original metaphysical model which has subsequently proved very fruitful within the Islamic world.
See also: Aristotelianism in Islamic philosophy; Epistemology in Islamic philosophy; Illumination; Islamic philosophy, modern; Mystical philosophy in Islam; al-SuhrawardiHOSSEIN ZIAI