What Does Empiricism Have in Common With Rationalism?

In the meditations descartes famously undertakes this philosophical project in which he says he is going to try to doubt everything. And so descartes doubts the existence of the external world, saying that it's possible that some demon is putting the idea of external world into his mind. He doubts his senses, whether they can be trusted, whether they are giving him correct impressions of the world around him. And finally gets to a single idea of which he cannot doubt, he says, which is that he is thinking, and therefore he exists. Is this famous formulation that we've heard before?