Beginning the Descent Into Rationalism - "Meditation 1" - Meditations on First Philosophy - Rene Descartes

In the introduction to Descartes' Meditations on First Philosophy Descartes makes it clear that he is setting out for a whole new type of argumentation. He is concerned that the Catholic Church is being undermined in his time, and desires to provide a new argument for the existence of God, and the immortal soul, which no person will be able to reject or deny because of its clarity. 1

Meditation 1 
He begins Meditation 1 by admitting that for a long time he has been aware that the beliefs he has held to are not foundational enough, that he can think of ways to challenge them, but has resisted the process of doing so. Beginning this meditation, though, he has finally carved out the time, and has the maturity, to undergo such a process as challenging all of his beliefs. Why would he do this? Well he is looking to ground his beliefs upon a foundation that cannot be put into any doubt whatsoever. 2 "Now for this object it is not necessary that I should show that all of these are false; I shall perhaps never arrive at this end. But inasmuch as reason already persuades me that I ought no less carefully to withhold my assent from matters which are not entirely certain and indubitable than from those which appear to me manifestly to be false, if I am able to find in each one some reason to doubt, this will suffice to justify my rejecting the whole." 3 

The Doubting the Senses
Descartes points out that if he can put into doubt his most foundational belief, then all his other beliefs come crumbling down as well. The first foundation belief that he attacks is that his senses are trustworthy and convey reality in a way which cannot be doubted. First, he points out that there are certain, obvious circumstances in which our senses make mistakes. For example, seeing something far off and believing it to be something different than it really is. But what about things that are up close to us? Is it necessary to doubt that I have hands or that there is a table in front of me? At first, it would seem impossible to doubt this, but then Descartes brings up those who are madmen that think many sorts of things about themselves that are not true. Would we be any different than these men if we were to simply assume our senses are accurate? Likewise, are there not many times in which we are confused between dreaming and reality? Do we not at some point all think we are living something, only to wake up and realize we are dreaming? 

On the other hand, could someone not make the argument that both reality and dreaming must at least share their content in common, thus one must be real. 4 This can be seen, for example, in the fact that all art, even of fictitious things that don’t exist, create those fictitious things from more fundamental things that do exist. An alien, though not existing, always in some way reflects what does exist. Thus, it is clear in the structure of our perception whether waking or sleeping there are certain universal and common components. 5 “To such a class of things pertains corporeal nature in general, and its extension, the figure of extended things, their quantity or magnitude and number, as also the place in which they are, the times that measures their duration, and so on. … For whether I am awake or asleep, two and three together always form five, and the square can never have more than four sides and it does not seem possible that truths so clear and apparent can be suspected of any falsity or uncertainty.” 6 

This does not save Descartes, though, as he admits that he can still put even such fundamental truths into doubt. He asks how it is that he is certain that he is not deceived in these more fundamental realities. How does he know that they really are so clear and obvious? The answer that he gives is that he believes that God is supremely good, and therefore would not deceive him. This is not good enough for him though, and he continues to even challenges this idea, as God certainly permits him to be deceived in some instances (as he already explained). Therefore, he decides that he is not even going to take the existence of God for granted. 7

Descartes then admits that such foundational and long-held beliefs are hard not to revert back to, but that if he is going to successfully create this new argument he must be totally methodical in his doubting. Only in doing this will he reach that which is undeniably true. In continuing then with his thought experiment, he permits the idea that since God allows us to be deceived some of the time, could it not be the case that all reality is the deception of an evil demon. Here he seems to reach a limit regarding the possibility of doubting what seems to be sure. Since Descartes has taken his doubts down to their foundation, from here he will begin to rebuild. He concludes mediation one saying: 8 “...And just as a captive who in sleep enjoys an imaginary liberty, when he begins to suspect that his liberty is but a dream, fears to awaken, and conspires with these agreeable illusions that the deception may be prolonged, so insensibly of my own accord I fall back into my former opinions, and I dread awakening from this slumber, lest the laborious wakefulness which would follow the tranquility of this repose should have to be spent not in daylight, but in the excessive darkness of the difficulties which have just been discussed.” 9

1 - Descartes, Rene. Meditations on First Philosophy. Introduction. 
2 - Fieser, James and Samuel Stumpf. Philosophy A Historical Survey With Essential Readings. Rene Descartes. Meditations on First Philosophy. Pg. 148.
3 - 148, 149
4 - 149
5 - 150
6 - 150
7 - 150
8 - 151
9 - 151