Descartes proved he exists by thinking

René Descartes famously declared, "I think, therefore I am." He systematically doubted everything, from his senses to the possibility of an evil demon creating a false reality. Yet, one truth remained undeniable: something had to exist to do the doubting. This thinking self became his bedrock for all knowledge, revolutionizing philosophy by making individual consciousness the starting point, not God or tradition. However, critics questioned if thinking truly requires a unified "I," or if thoughts could simply occur without a distinct thinker. This led to the enduring "mind-body problem" – how does a non-physical mind interact with a physical brain?