-

The history of philosophical thought in west has, once in a while, witnessed the appearance of a philosopher who has made a tremendous impact on the world of thought for years. Descartes is an outstanding example of this historical reality who commenced his philosophy with "imperative doubt" on which he based a philosophical structure. The major pillar of this type of thought was "I think, so I exist" which engaged the philosophers' attention for decades and what numerous books were written to clarify, verify, or reject this thought.
In spite of the criticisms made against this philosophical method, its tremendous impact on all post-Descartian philosophical speculations cannot be ignored. This philosophical tradition originated the most fundamental thinking lines in the
west, the influence of which is quite evident in the context of western philosophical views.
In this artica1e an effort is made to examine this major principle of Descartes' philosophy as far as possible and estimate the extent of its influence on the other dimensions of this great
philosopher.