Is being an internalist smart?

On monday we talked about how Descartes was an internalist. He concluded his own beliefs first, before making conclusions about the world around him. To me, this is just setting yourself up for failure. As we have discovered, just because you believe something doesen't mean that you are correct. It makes more sense to be a realist, in my opinion. If you take percievable facts from the world around you, and then make up a set of beliefs, you are more likely to have a more accurate set of beliefs than you would otherwise. What do you think?