نشریه حکمت سینوی
پیاپی 50 (پاییز و زمستان 1392)

Avicenna is undoubtedly one of the outstanding scientists and perhaps the most prominent one in the history of Islamic-Iranian civilization. After a lifetime of trying to describe, explain and complete the Greek intellectual heritage, Avicenna admitted (in the introduction of Mantiq Al-Mashriqiyin) to have achieved a realm of philosophy which he construed as "oriental philosophy''. Avicenna's oriental logic can be defined and explained according to the very oriental philosophy in terms of method and content. The issue is what the characteristics of this oriental philosophy and particularly, oriental logic is. Since there is not direct and abundant evidence in "surface" as documents, we try to reach the conclusion by a range of indirect and limited evidences in "depth". In this paper, two different and yet consistent features of Avicenna's oriental logic are inferenced and introduced. In the first sense, oriental logic can refer to a range of "non-Aristotelian innovative and established systems" in the East, and in the second aspect, it can be an oriental horizon and dawn to establish a "fuzzy logic" which is considered today multi-valued and infinite-valued logic.

According to a common definition, the argument of truthful ones is an argument in which the existence of Necessary Being is proved with no presumption of the existence of the possible being (creatures). Avicenna proposed different versions of this style of argument and the version in the book of Nejat is one of them. This paper is intended to examine the possibility of proving the logical validity of this version in first-order predicate logic and explain the principles which the argument is based on. In this way, it becomes clear to what extent Avicenna's version is in accordance with the criteria he himself introduces for the argument of truthful ones. In this respect, while providing a clear exposition of the version in the book of Nejat, bugs on some of the statements and proposals to obviate them in terms of replacement arises. Then explaining the concepts and premises which the argument in the book of Nejat is besed on, it is formulated in first-order predicate logic with its full proof. Finally, the proposed model's accordance with the presented criteria for the argument of truthful ones will be shown.

There are novel theories in epistemological realm of Avicenna's thought which, despite full incidence in the thoughts of philosophers after him, can be observed explicitly or implicitly in Avicenna's novel ideas. This feature makes it possible to divide the epistemological field of Avicenna's thought into two areas: peripatetic-Aristotelian and oriental. Following his peripatetic predecessors, Avicenna considers soul's perceptions only acquired and relying on the epistemological theories of abstraction and peeling, explains the quality of soul's acheiving these perceptions; however, in his oriental thought, Avicenna ascribes acheiving and preserving intuitive and non-acquired perceptions to the powers of common sense and image due to his novel approach towards these two powers in the last chapter of Isharat. It means that soul's perceptions can also be intuitive and non-acquired in Avicenna's philosophy as well as it is essential not to explain the quality of achieving these perceptions by the process of epistemological abstraction. Understanding soul's existential intensity and considering it as its epistemological hierarchy, unlike the dogmatist position, Avicenna retains a kind of approach in Islamic epistemology which makes it possible to achieve knowledge according to the reality.

Avicenna is one of the philosophers who binds prophecy and politics, intellect and revelation as well as philosophy and shariah together relying on al-Farabi's legacy. He introduces the establishment of a political system stemming from shariah and rational religion as the way of saving the society and accordingly, establishes his favorite theory for ideal government and calls the society which is administered by such government a just city. Reviewing just city theory in Avicenna's view and its adapting to al-Farabi's ideas, on the one hand, their affecting and being affected as well as their opposition and consensus become clear and on the other, the role and position of Avicenna's political thought is identified. There are similarities between the views of al-Farabi and Avicenna such as human's being civil in nature, conformity and harmony between the system of universe and the system of the city, building city on the basis of virtue, morality and justice, as well as monopoly of sovereignty to the owners of knowledge of the facts of the supreme world. While their ideas are different on the topic of the chief of the city and his attributes as well as city levels and its details the approach of these two philosophers divides.

There has always been this supposition in our philosophical tradition that Ibn Sina at first did not understand the Metaphysics of Aristotle and then by the help of Farabi's book – which was devoted to aghraz al – mabadaltabiah-could understand it. This supposition for this reason prevails among the historians of Islamic philosophical thought that Ibn Sina himself affirms in his autobiography that has repeatedly read the Metaphysics of Aristotele but has not understand it. But this understanding of Shaikh's autobiography-given Ibn Sina's genius and also by considering the brevity of Farabi's book – it seems susceptible to criticism. In this paper on the basis of proofs and evidences from other writings of Ibn Sina a new understanding of his autobiography is presented which differs from common understanding and it is shown that Ibn Sina's intention is not that he had difficulty in understanding the content of the Metaphysics but he has not been in agreement about the formulation of some commentaries of it.

Providing a rational explanation of the process of revelation is a common viewpoint which has been proposed by the Islamic philosophers. Offering a plan of human thought and reasoning system, Avicenna, as one of the pioneers of Islamic philosophy, attempted to include the process of receiving revelation by the prophet in this scheme; so that he proved revelation as having full rationality which is only available for the prophet. Avicenna's approach in epistemic explaining of revelation becomes clear in dealing with other philosophical approaches. For example, al-Farabi associates revelation to the Prophet's power of imagination and distinguishes sage and prophet in this way: the sage is connected to the active intellect by education in the level of acquired intellect, while the prophet comprehends these facts relying on his power of imagination without education. So we can conclude that in terms of intellect actuality, a sage is higher than a prophet. However, in view of Avicenna, recipient of revelation is the sacred intellect of the prophet which is the greatest human intellectual capacity and is available only to the prophet, and never the sage and philosopher have the ability to achieve this level.

In the problem of the yardstick of effect's need to cause it is well-known that the pre-Sadrian philosophers believe in the essential possibility of effects, that is to say they held that the non-requirement of essence of effect in relation to being and non-being is the factor of effect’s need to cause. In contrast, Sadr al-Mutaallihin on the basis of fundamental principle of principality of existence and non-reality of contingent beings not in their quiddity and therefore believes in the theory of existential poverty. With further investigations and tracing the roots of this theory, in some of Ibn Sina's works it can be said that he also has paid attention to the theory of existential poverty. Ibn Sina by distancing himself clearly from Aristotelian tradition on the problem of causality and attention to divine agency, regards the cause as giving existence to effect and with different statements declares that the poverty of need of effect to cause lies in his existence. Therefore, besides rejecting the view of theologians who considered temporal contingency the yardstick of the need to cause, in comparison to previous sages says who regarded the yardstick of the need to cause in the nature of the non-requirement of effect, Ibn Sina goes a step further and in some statements explicitly states that the factor of effect's need to cause is the reason of its dependant existence which is the very reality of the effect. However, giving the scattered and different statements of Ibn Sina on the yardstick of effect's need to cause he can not be regarded as supporting the theory of existential poverty. But by tracing the indications of this theory in his works it shows that he can be regarded as the precursor of this novel Sadrian theory.