Final answer:
Descartes' statement 'I think, therefore I am' asserts the certainty of one's existence through the act of thought. It implies that thinking is proof of existence, which supports Descartes' dualist belief that the mind can exist separately from the body. However, modern science has shown that thought is linked to physical brain processes.
Step-by-step explanation:
When René Descartes said, “I think, therefore I am,” he was making a fundamental statement about existence and certainty. Descartes asserted that the very act of doubting one's own existence serves as proof of the reality of one's own mind; if he is thinking, then he must exist. This concept is known as cogito, ergo sum and establishes that thought does not depend on physical existence.
Descartes believed that knowledge could be obtained through reasoning alone, segregated from experience. This means that certain truths, such as mathematical truths, are inherent to our reasoning rather than learned through experience. For Descartes, the mind is a non-material entity that can exist independently from the physical body. This belief is part of his broader dualism doctrine, which posits that there are two types of substances: the mental and the material.
However, modern science challenges Descartes' claims, providing evidence that thinking is deeply connected to physical processes in the brain. This means that the assertion “I think, therefore I am” may guarantee one's existence, but it does not prove the existence of a mind separate from the body, as Descartes had proposed.