Discourse On Method Part IV
In part IV of Descartes' Discourse, Descartes continues his quest for knowledge of truth. In this particular section, Descartes focuses his discussion primarily on how to determine what we know with certainty to be true. Here, Descartes introduces his infamous method. Systematically he doubts everything and, afterwards, tries to see if anything remains that can be known with certainty.
Descartes embarks in his journey by taking a reverse approach from earlier parts of the Discourse. In Part IV, he writes that he will doubt all knowledge that comes from the senses, with the observation that we can wrongfully interpret sensory input in the external world.
Next, Descartes casts off inductive reasoning, finding it insufficient to provide indubitable truth.. Descartes reasoning moves even deeper after he calls these two forms into question, however. He recognizes that in order to doubt something, something has to exist in the first place to provide the conditions for the possibility of doubting. He says that this something is thought itself:
After this I considered in general what is required of a proposition in order for it to be true and certain; for since I had just found one that I knew to be such, I thought that I ought also to know what this certainty consists in. I observed that there is nothing at all in the proposition ‘I am thinking, there I exist’ to assure me that I am speaking the truth, except that I see very clearly that in order to think it is necessary to exist. So I decided that I could take it as a general rule that the things we conceive very clearly and very distinctly are all true. . . . (Descartes n.d., p. 14)
It is in this context which Descartes articulates possibly one of the most famous quotes in Western philosophy, and the point at which he assigns indubitable truth to the fact of existence. This brief moment of calm does not linger for awhile, however. Soon after Descartes admits, “there is some difficulty in recognizing which are the things that we distinctly conceive” (Descartes n.d., p. 14)
Realizing that the very act of doubting implies that he as a being is not perfect, because, as he reasons, doubting implies imperfection or a lack while knowing is the opposite. (Descartes n.d., p. 5) Descartes then decides to look into his own ability to think “of something more perfect than I was; and I recognized very clearly that this had to come from some nature that was in fact more perfect”. (Descartes n.d., p. 14-15)
Descartes observes what he finds about the truth value in perceptions of physical object. He writes: “I observed nothing in them that seemed to make them superior to me” the result of which is that “I could believe that, if they were true, they depended on my nature in so far as it had any perfection, and if they were not true, . . . they were in me because I had some defect”. (Descartes n.d., p. 15) However,
the same could hold for the idea of a being more perfect than my own. For it was manifestly impossible to get this from nothing; and I could not have got it from myself since it is no less contradictory that the more perfect should result from the less perfect, and depend on it, than that something should proceed from nothing. So there remained only the possibility that the idea had been put into me by a nature truly more perfect than I was and even possessing in itself all the perfections of which I could have any idea, that is, . . . by God. (Descartes n.d., p. 15)
Descartes draws an example from geometry to supplement this point: for there to be a triangle, the object in question must conform to certain rules. However, “for all that, I saw nothing which assured me that there existed any triangle in the world” (38) which could perfectly meet these specifications. By the same token, the perfection of God also remains an ideal and his existence “is at least as certain as any geometrical proof”.(Descartes n.d., p. 16)
The reason for such doubts concerning the existence of God, Descartes argues, is that “they never raise their minds above things which can be perceived by the senses: they are so used to thinking of things only by imagining them (a way of thinking especially suited to material things) that whatever is unimaginable seems to them unintelligible”. (Descartes n.d., p. 16) Descartes writes that everything comes from the senses which is in the intellect exceptfor God.(Descartes n.d., p. 16)
In this light, Descartes then draws the conclusion that “trying to use one’s imagination in order to understand these ideas is like trying to use one’s eyes in order to hear sounds or smell odors” (Descartes n.d., p. 16) Our senses do not assure the truth that the objects which appear before them are real, and this is because both our senses and our imagination requires our intellect to perceive and process this data. Descartes points out that all those objects “of which they may think themselves more sure – such as their having a body, there being stars and an earth, and the like – is less certain”, because “we cannot reasonably deny that there are adequate grounds for not being entirely sure about them”.(Descartes n.d., p. 17) One example of this is the common experience of being in different realities during one's sleep.
The surprise to this argument is Descartes' conclusion. He reasons that the only way around this doubt is to “presuppose the existence of God” for the assumption that “everything we conceive very clearly and very distinctly is true, is assured only for the reasons that God is or exists, that he is a perfect being, and that everything in us comes from him. (Descartes n.d., p. 17) From this argument it follows that we make errors and misinterpret reality with delusions because we are imperfect as beings ourselves: “if we did not know that everything real and true withing us comes from a perfect and infinite being then, however clear and distinct our ideas were, we would have no reason to be sure that they had the perfection of being true”. (Descartes n.d., p. 19)
Descartes then draws the conclusion that for the imaginations we experience in our dreams, no matter how real they might appeal to our sensory faculties, they “should in no way make us doubt the truth of the thoughts we have when awake”. (Descartes n.d., p. 19) In other words, one could say that the inter-mediator between what we dream and what we think should not be our senses if we are to arrive at the truth.
The major thrust of reasoning here hinges on the mind's possibility to conceive of perfection to begin with. Our own thoughts could be figments of our own mind, Descartes finds that to conceive of perfection itself necessitates the existence of a perfect God. To do so would be a contradiction, because it would suggest that the concept of a perfect God was dependent upon an imperfect human.
References
Bicknell, J. (2003). Descartes's rhetoric: Roads, foundations, and difficulties in the method. Philosophy and Rhetoric, 36(1), 22-38.
Cherubi, R. (n.d.) Some notes on Descartes' Discourse Part IV. Retrieved from http://mason.gmu.edu/~rcherubi/ndis4.htm
Descartes, R. (n.d.) Discourse on the Method (Part IV). Retrieved from http://www.earlymoderntexts.com/pdf/descdisc.pdf.
