René Descartes really changed the way we think about philosophy today, especially in the rationalist tradition. His belief that reason is the key to knowledge set the stage for many thinkers who came after him.

To start with, his idea of doubt was groundbreaking. By questioning everything around him, he encouraged other philosophers to find certainty through logical thinking. This way of thinking influenced later philosophers like Spinoza and Leibniz, who built on Descartes' ideas about skepticism and using math in philosophy.

Also, Descartes’ famous saying, “I think, therefore I am,” shows how important it is to recognize ourselves as thinking beings. This became a crucial idea for future rationalists. For example, Kant took this focus on the self and used it to create his own ideas about knowledge and morals, mixing rationalism with the ideas of experience.

In addition, Descartes' idea of dualism—separating the mind from the body—sparked a lot of discussions. Philosophers like Malebranche and later Hegel took on this separation, either challenging or changing Descartes' views on existence.

It's also worth noting that Descartes faced criticism. Many people believe that his focus on reason downplays the importance of what we experience through our senses. This has led to ideas from empiricists who argue against him. Still, even with these criticisms, Descartes’ influence is clear, as people continue to discuss his original ideas.

In summary, Descartes put a strong spotlight on reason, questioning, and individual thought. This sparked significant changes in the rationalist tradition and influenced many philosophers for generations. At the same time, his work has led to ongoing discussions that are still relevant today.