Descartes was a philosopher who believed a lot in rationalism, which is the idea that we can understand things through reason and thought rather than just what we see or experience. In his work called the Method of Doubt, he aimed to find a strong basis for science that didn’t rely on the doubts that can come from our senses—like what we see or touch, which he thought could sometimes be misleading.

To figure out what we can really believe, Descartes questioned everything, even the existence of the outside world. This led him to his famous saying, "Cogito, ergo sum," which means "I think, therefore I am." This shows that he valued reason and what we know innately, rather than just what we can see or touch.

However, some people think that Descartes' way of doubting everything can be a bit too extreme. If he doubts all our experiences, he misses out on the real-life understanding that comes from living and learning. Many philosophers believe that knowing things through our feelings and experiences is very important, and they think a better mix of these ideas could be helpful.

Even with these concerns, Descartes' method of questioning has an important role. It helps clear away false ideas and doubts about our senses. By focusing on rationalism, he puts reason at the forefront of understanding, which helped shape modern philosophy and science. His work encouraged people to stop looking only to tradition and authority and start questioning and thinking for themselves.

In short, while some might think Descartes' beliefs are a bit harsh, they actually help us deal with the tricky ways our minds work and the problems that can come from relying only on our senses. His method still encourages us to think critically about what we know today, reminding us to find a balance between reasoning and understanding through experience.