Simplified Reason

I: Many of the things I used to be certain of, I now know to be nonsense. To find some firm foundation for science, I must try to establish what is absolutely true. So, I'll imagine that some evil genie is deceiving me about absolutely everything.II: I can't be sure of the things I know, but I can be sure that I know things. I think therefore I am.III: All ideas have a cause. The cause must either be inside me, or something else. Infinity and perfection are not within me, so the idea of an infinite and perfect God must have come from something outside me, so God must exist.IV: A perfect God would not cause the imperfection of deceit, so He is not deceiving me about the things of which I have clear and certain knowledge.V: I am certain that I know material objects, inasmuch as I can define them by mathematics. This knowledge doesn't make things exist, but my knowledge of God makes me certain that they are something.VI: I imagine that I have a body and that my knowledge comes from my senses. Using several senses together I can determine what is true. But we don't always have time for this, so we often make mistakes.