Descartes, also called a dualist, claimed that the world had two basic substances. Those substances are matter and spirit. The physical universe, which our bodies are a part of is matter. The spirit is the human mind, which interacts with the body but can exist without it. He believed that matter could be understood through simple concepts. One of those concepts would be that he borrowed from geometry. In Descartes view, the whole world was created by God. He thought that God was resembled as the human mind.