Then again, this does not guarantee that our self image is that of a human being. After a process of elimination, the only thing one can be sure of is the existence of self. In order to think, one must exist and that is indubitable because the fact that one is thinking is evidence that one exists. .
Ever since there were philosophers, the question whether God exists or not have been the question many philosophers tried to solve. Many would have been satisfied with proving God's existence, but Rene Descartes took it to the next level. He claimed that God exists and it is indubitable that God exists. Many have studied Descartes theory on this matter and several found that his reasons for God's indubitable existence conflicted with his method of doubt; among these scholars included Elliot Sober. Descartes believed that such a being as perfect as God cannot be created by just our imagination. You cannot create something out of nothing. Thus the only reason why we are able to envision a perfect being is because there actually is a perfect being in which we call God. This, controversially, attacks his own method of doubting and his philosophy on knowledge. He stated that knowledge that contained any ounce of doubt should not be considered as true knowledge. However, his explanation for the indubitable existence of God is suggesting that we should trust our senses and subconscious because if we have this idea of a perfect being, then the cause of that idea must be a perfect being. This problem was later known as the Cartesian Circle. .
Descartes overall objective was to question what knowledge he had were absolutely true. In order for him to explore bigger philosophical questions such as the existence of god, he needed to discard all of his previous doubtable principles that supported everything he once believed. First he examined his senses and came to the conclusion that they are not to be completely trusted since senses has the capability to deceive him.