Perception provides the hope for discovering not just the essence of matter, but its existence. His first consideration is that the existence of God has to be demonstrated philosophically, besides the theological reasons for belief, particularly if we consider to make a demonstration for the non-believers. The genuine properties of things are not the idiosyncratic sensory properties that have nothing to do with each other fire is warm, fire is red : there is the one reality responsible for both sensations, namely matter in motion. For example, if the idea of a creature with the head of a , the body of a and of a was constructed and the question asked if the creature had a large intestine, the answer would have to be invented. So he decides to suspend judgment. Descartes shows two ways in which mind and body seem to have different properties, and how, hence, they must be different things.
Moreover, the believers could be accused of making a , when saying that we must believe in God because of the Scriptures, and in the authority of the Scriptures because they have been inspired by God. By supposing that there is merely a rational distinction between essence and existence abroad in all things, Descartes seems to confirm this objection. Beliefs that are irresistible, indubitable, are the best beliefs on Descartes' criteria , and at the same time the least open to choice. We can imagine purple lions, but not a non-existent God. The idea is not that these doubts are probable, but that their possibility can never be entirely ruled out. At this point, he has only shown that their existence could conveniently explain this mental process.
The intellect does not provide me with ideas that are all clear and distinct, and the will is free to affirm or deny any of them. We should resist believing anything that is not 'clear and distinct'. However, maybe this isn't because he's limited, but because we're talking nonsense when we ask God to do these things. Is self-deception involved in Pascal's Wager? And I can do it! Since I only can be certain of the existence of myself insofar as I am thinking, I have knowledge of my existence only as a thinking thing res cogitans. God could make even our conception of mathematics false. The foundations for knowledge Descartes established would go on to influence a plethora of other philosophers and philosophical works. Another kind of case is presented by self-fulfilling beliefs.
We are sometimes deceived through perception, or dreaming : what reason to we have for thinking we are not always deceived? After all, he can think up all sorts of shapes that he has never seen and derive their properties as clearly and distinctly as he does with those of the triangle. That, briefly stated, is the Ontological Argument. Imagine something that is omnipotent. If I can clearly and distinctly understand A apart from B, and vice versa, then A and B are metaphysically distinct, and could exist apart. Surely Descartes' own commitment to finding indubitable beliefs is a commitment to finding beliefs that I cannot resist.
The universe moves like a complex clock, with everything pre-determined and in accordance with the laws of matter. In Anselm's day, a monk named Gaunilo suggested that we could use the same argument to prove that the perfect island that island which is greater than all other islands must exist. For example, when I imagine a triangle even if perhaps no such figure exists outside my thought anywhere in the world and never has, the triangle still has a certain determinate nature, essence, or form which is unchangeable and eternal, which I did not fabricate, and which does not depend on my mind. This is the Ontological Argument for God's existence. The Painter's Analogy, which draws on the Dream Argument, concludes that mathematics and other purely cerebral studies are far more certain than astronomy or physics, which is an important step away from the Aristotelian reliance on the senses and toward Cartesian rationalism.
The gap looks too big to jump. Cartesian Metaphysics, Cambridge University Press. This discussion is important because it provides him with a first and general opportunity for indicating how one proceeds from clear and distinct ideas to the world, and because it indicates something about the world itself independent of our thoughts about it. Leibniz: Determinist, Theist, Idealist, New York: Oxford University Press. I gradually find that I have achieved the necessary belief, and thereby saved myself from the risk of hell. In this understanding of exists, the divine attributes that are predicated of God including the attribute of existence that Descartes wishes to predicate of God can only describe what God should be like provided He actually exists.
Some of the things I clearly and distinctly perceive are obvious to everyone, while others are discovered only by those who look more closely and investigate more carefully; but once they have been discovered, the latter are judged to be just as certain as the former. They 'indicate, or attempt to indicate, the necessary style of the philosophycal beginning'. So the essence of God implies his existence. Draw a triangle on the board. Therefore my mind and body are metaphysically distinct and could exist apart. His aim is to apply a method to demonstrate these two truths, in a so clear and evident manner that result to be evident. Rather than inquire into the things themselves, he inquires into her ideas regarding material things.
There is knowledge of the self, its existence and essence; knowledge of God, his essence and existence; and knowledge of matter, in so far as its essence is described by the intellectual science of geometry. One problem then with the theory of real distinction, at least as espoused by many of Aquinas' followers, was that it reified essence and existence, treating them as real beings in addition to the created entity that they compose. It seems that you cannot believe something in the teeth of overwhelming evidence against it. Since the ontological argument ultimately reduces to an axiom, the source of an objection according to Descartes' diagnosis is the failure of the objector to perceive this axiom clearly and distinctly. I may choose to act rightly; or I may choose to act wrongly.