哲学探究における数学

ファーラービーを哲学者として評価するための視座

抄録

The purpose of this article is a reinterpretation of Farabi's philosophy. Several difficult questions have arisen concerning Farabi's Trilogy, which consists of Tahsil al-Sa'ada, Falsafat Aflatun and Falsafat Aristutalis, one of which is how to understand the relationship among the three works. But in view of the general theme of the three works, i. e. investigation (fahs), and on comparing them with another investigative work, Kitab al-Huruf, we can see how Tahsil al-Sa'ada relates to the other two works.
In the course of this examination, we must, at the start, solve the difficult question, how to interpret Farabi's assertion: ‘philosophy was completed with Aristotle’, which appears in two places (one in Tahsil al-Sa'ada, and the other in Kitab al-Huruf). If we take this assertion, it would mean that Farabi made no contribution to philosophy- he was only a transmitter, not a true philospher. However by considering Farabi's thought on the history of mathematics and the relation between mathematics and philosophy (especially logic), this phrase can be interpreted with subtle shade. (1) It is safe to say that in the age of Plato and Aristotle, as far as Farabi thought, mathematics was not fully developed, and so he could not really have believed that philosophy had been completed, for it seems that he thought mathematics and philosophy go hand in hand. (2) What he called into question when he discussed mathematics was not substantial matters or mathematical problems, but methodology. So we infer that his treatment of philosophy too is about methodology.
This line of thought can show us the process of his introducing a mathematical methodology to his philosophy in the Trilogy. Now we can see how he describes in Tahsil al-Sa'ada the way his own philosophical investigation differs from that of Plato or Aristotle as seen in Falsafat Aflatun or Falsafat Aristutalis. Mathematical methodology has affected on Farabi's philosophy in various ways. This paper suggests some aspects of this effect, for example, we describe how it works in metaphysics and politics.
This article cannot follow all the consequences of this thought, so it remains only preliminary research, but this step, I trust, is an important one for our understanding of Farabi's philosophy, especially of how he was a ‘true philosopher’.