Short answer: Descartes' doubt was like WWI - the doubt to end all doubt. Only by doubting everything could Descartes hope to find anything that was certain (even if the only certainty is that nothing else is certain!).
Descartes found it impossible to doubt his own existence. The reason for this was that he felt that thoughts had to come from himself.
That he is sentient ie that he thinks.
he believed if you can doubt it, it must not exist.
For Descartes, this was the fact that he existed as a thinker. He was perfectly sure he was thinking; and he was likewise convinced that to be thinking he had to exist as some kind of substance.
Short answer: Descartes' doubt was like WWI - the doubt to end all doubt. Only by doubting everything could Descartes hope to find anything that was certain (even if the only certainty is that nothing else is certain!).
Descartes' radical doubt refers to his method of systematically doubting all beliefs and knowledge in order to establish a foundation of certainty upon which to build his philosophy. By doubting everything that can be doubted, Descartes aimed to arrive at indubitable truths that could serve as a solid basis for his philosophical system.
Descartes believed that doubt was a crucial tool in the search for truth. By subjecting all his beliefs to doubt, he aimed to find a foundation of knowledge that could not be doubted. This led him to his famous statement "Cogito, ergo sum" (I think, therefore I am), which served as the starting point for his philosophical system.
Descartes found it impossible to doubt his own existence. The reason for this was that he felt that thoughts had to come from himself.
Descartes' concept of systematic doubt involves doubting everything that can be doubted in order to arrive at indubitable truths. By doubting the reliability of the senses, memory, and even the existence of an external world, Descartes sought to establish a foundation of knowledge based on clear and distinct ideas that could not be doubted. This method of doubt is a key component of his philosophical method known as Cartesian skepticism.
Descartes' method of doubt was a systematic approach to examine the foundations of knowledge by doubting everything that could possibly be doubted. He aimed to find a firm foundation for knowledge by doubting even his own existence, ultimately arriving at his famous conclusion, "Cogito, ergo sum" (I think, therefore I am). Through this method, Descartes sought to establish a new epistemological foundation based on indubitable truths.
He can not doubt that he thinks, therefore he exists.
That he is sentient ie that he thinks.
Descartes' theory of knowledge was to doubt all things and accept as knowledge the things that could not be doubted
Descartes hopes to find out what he can know for certain, without any doubt, about the world and nature.
he believed if you can doubt it, it must not exist.
Descartes aimed to prove that he could establish certain knowledge by doubting everything that could be doubted, ultimately leading to the famous conclusion "I think, therefore I am" as the foundation of his philosophy. He sought to find a firm foundation for knowledge that was beyond doubt.