At the start of the meditation, Descartes begins by rejecting all his beliefs, so that he would not be deceived by any misconceptions from reaching the truth. Descartes acknowledges himself as, "a thing that thinks: that is, a thing that doubts, affirms, denies, understands a few things, is ignorant of many things" He is certain that that he thinks and exists because his knowledge and ideas are both clear and distinct'. Descartes proposes a general rule, "that whatever one perceives very clearly and very distinctly is true" Descartes discovers, "that he can doubt what he clearly and distinctly perceives is true led to the realization that his first immediate priority should be to remove the doubt" because, "no organized body of knowledge is possible unless the doubt is removed" The best probable way to remove the doubt is prove that God exists, that he is not a deceiver and "will always guarantee that any clear and distinct ideas that enter our minds will be true." Descartes must remove the threat of an invisible demon that inserts ideas and doubts into our minds to fool us , in order to rely on his clear and distinct' rule.
In constructing his argument for God's existence, Descartes analyzes several aspects of the nature of human thought. He begins by outlining the various types of thoughts we have, which include ideas, thoughts, volitions and judgments. Ideas, or images of ideas can only exist within the mind and are certain of existence. Volitions, or choices