a.Methodic doubt: Descartes was dissatisfied by the disagreement and quarrels among philosophers and therefore thought that philosophy needed a new method. He then went on to adopt the method of mathematics in philosophy. He therefore resolved to doubt every fact and truth he had been taught or had learned which could not pass his test for truth, which is being a clear and distinct idea. However, whatever passed this test was considered by him as self-evident. From these self-evident truths, other truths were deduced. The only thing he did not doubt was the proposition cogito ergo sum (I think therefore I am).
b. This is therefore the first reality he discovered through his method, that ...
Methodic doubt, the first truth or the cogito, Descartes and the ontological argument, the mind-body dualism and knowledge in the Cartesian system.