Postmodern thinkers have really questioned what Descartes said about the self and knowledge.

Descartes is famous for saying "Cogito, ergo sum," which means "I think, therefore I am." He believed that thinking and being rational were the keys to understanding ourselves and the world around us.

However, postmodernism challenges this idea. It says that our identities are not just about being alone and thinking logically. Instead, our sense of self is shaped by the world and culture we live in. It’s not simple or fixed; it’s influenced by many factors all around us.

Philosophers like Foucault also argue against the idea that there are universal truths, which is something Descartes believed in. They suggest that knowledge isn't just found through reason. Instead, it is shaped by power and society. This means what we think of as knowledge can change and is dependent on different situations, rather than being always true.

Another thinker, Derrida, talks about deconstruction. This idea questions how language works and how we find meaning. They say that words and ideas can never perfectly express reality. This challenges the certainty that Descartes thought was stable in his philosophy.

In short, the postmodern view shows us that the self is not just about reason; it’s also complicated and influenced by everything around us. It tells us that knowledge is something we create rather than something we simply discover. This has changed how we think about Descartes and his ideas in modern philosophy.