While it seems that we can be confident that objects in the physical world are indeed, certain, Descartes does not view them this way. He cites the fact that when we are dreaming, we can perceive physical objects which we would think are certainly in existence when in reality they are not because it is a dream. He takes this one step further though to show how it is possible that everything we perceive is simply an illusion being fed to us by something else. There would be not way to prove or disprove this, so we can not use physical objects in the world as a basis for certainty. This leads to the third thing which is to be doubted, mathematics. While it was accepted that math was the absolute picture of certainty, it was not seen as such by Descartes. For Descartes, the idea that two plus two equals four can not be held in a regard to certainty because it is also possible that there may be some kind of illusion being fed to us that tow plus two equals four, when in fact, it may very well equal five. We would have no way of knowing because the source of the illusion would trick us every time we come close to discovering the error in basic or complex mathematical …show more content…
Descartes goes by attempting to discover the source of our ideas of perceptions in order to determine if they are valid. He concludes that if God exists, God is all good, meaning that he would not deceive us with the perceptions he sends us. Therefore, if God is what gives us our ideas, then we can conclude that our perceptions are valid. In order to prove the existence of God, Descartes examines where our ideas come from. He concludes that there are three possibilities. One, that our perceptions and ideas are caused by physical objects, Two, that they are caused by ourselves, or three, that they are caused by God. The first of these can be overruled because it is the very nature of physical objects which he is trying to discover. The second, that we give ourselves these ideas, Descartes sees an invalid as well because he believes that since we are finite, and God in infinite, we could not conjure up the idea of God. It is for this reason that He believes that God must exist because our idea of his in inert. Meaning it was planted there in our nonphysical DNA so to speak. He concludes that because God does exist, we can trust that our perceptions of physical objects are to be held with