Descartes relies on his study of Mathematics to guide his thought on the desirable lines. He establishes the four rules of Method which he presents as valid for study of all sciences. They are: Rule of Intuition, Rule of Analysis, Rule of Synthesis, Rule of Deduction
Now Descartes does not accept the evidence of the senses to ascertain the existence of any material object since senses may be capable of deceiving us. So he rejects anything which should have the slightest cause of doubt , to find if there is anything which is absolutely indisputable and obvious.
It is then that he arrives at Cogito Ergo Sum' I think therefore I am, for doubting is thinking and is linked to his existence. I exist' here means that I exist as a thinking being'. Further he makes a distinction between mind and matter. He feels his thinking being is the mind, the self or soul and is independent of outside world, i.e. matter. This Cartesian Dualism can be in a few ways compared to the Samkhya dualism.
Here it is doubtful as to how he establishes the existence of matter at all when all he can prove is that he is a thinking being. Also the idea that matter is absolutely independent of mind and the two are mutually exclusive entities sounds problematic. If it were so, how at all to explain the relation that the two share or rather seem to share.
Next Descartes sets upon establishing the existence of God. And once that is done, it is easy to show that, as a perfect being, he cannot deceive us and hence we can place our confidence in him, in the clear and distinct ideas that we...