by Kolbitar » September 25th, 2007, 12:28 am
Hello Chad.
::He doubts all "except what is necessarily true." What is necessarily true turns out to be a whole lot. His project is more to discover how he knows it - and the answer is that he is a cognitive thing. Would this render a better understanding of Descartes?
I'm not sure that "what is necessarily true" actually "turns out to be a whole lot." What Decartes takes as necessarily true is only that, which has mathematical certainty. What is mathematical certainty to Decartes? It is nothing other than clear and distinct ideas - it's not enough for an idea be clear, it also must be distinct. Thus Etienne Gilson writes:
…all that can be clearly and distinctly known as belonging to the idea of a thing can be said of the thing itself… But what is it, to know something distinctly? When a mathematician knows a circle, he knows not only what it is [it's definition]`, but, at the same time, what it is not. Because a circle is a circle, it has all the properties of the circle, and none of those that make a triangle a triangle, or a square a square. Philosophers [according to Decartes] should therefore proceed on the same assumption.
Decartes took ideas as the very things themselves, as that which we know, instead of -- as the Realists before him did -- that *by which* we know things (akin to eyes through which we see). In doing so, he implicitly rejected a large bit of accepted epistemology to which he had no later recourse when trying to salvage the world of our senses. The idea of a soul -- i.e., a mind/body composite - contains ideas that are separable. Instead of taking the mysterious mind/body fact as it stands, Decartes insisted on subjecting it to an arbitrary standard of clearness and distinctness, which inevitably led him to the "ghost in the machine" fiasco. On the one hand "I think therefore I am" is clear, yet on the other it is distinct in so far as it leaves no room to say about physical reality that it is anything other than illusion. So, to posit the real existence of physical reality outside our minds, which cannot be done if ideas are what we know, Decartes had to draw upon the idea of God, which, in turn -- he endeavored to show -- would secure our conviction that the physical world exists. Thus Decartes drew upon the ontological argument for God's existence (which uses an idealist basis), then proceeded to argue that such a God would not deceive us.
There's a number of things to be said about all this -- and philosophers did say them. For instance, if God gave us the rational means to figure out that reality is an illusion, then God is not deceiving us; perhaps He gave us these "illusions" for His own purposes which weren't meant to include their representations as actual existences outside our minds - that is conceivably our mistake, not His.
Or take Decartes clear and distinct idea mind. Mind is a thinking substance; an idea which, when pushed to the point of distinctness, excludes extension in space (i.e., excludes the idea of "body"). This thinking substance idea is clearly refuted by the facts of our experience, for a thinking substance can do nothing but think-yet I do other things than think, and sometimes (like when I sleep) I don't think at all.
Accepting Decartes' assumption that ideas are what we know, the empiricists pointed out that the idea of cause and effect is anything other than clear and distinct. How, then, can God have caused an idea of Himself and/or of physical reality when cause is an idea that lacks the very certainty upon which Decartes philosophy claims to rest? The failure of Decartes thus gave rise to the success of Hume. If an (intellectual) idea -- such as God, or mind -- does not spring from a sense perception (again, sense perception is no longer a means of knowledge, as it was to the realists, but that of which we're directly aware) then naturally, since a cause of sense perception is meaningless, so is anything purportedly outside of it causing it. Sense experience is certain - because it is what it is; and mathematics has certitude because it expresses relations between ideas: all the rest, according to Hume (proceeding on Cartesian assumptions), is meaningless.
Incidentally, this Cartesian method takes many forms of "rationalism", depending on which area of thought it's applied: from Atheism to Deism to Unitarianism, it works to clear away any undesired implications which cannot stand the scrutiny of being clearly defined and distinctly understood.
It’s all very interesting…
Jesse
The man who lives in contact with what he believes to be a living Church is a man always expecting to meet Plato and Shakespeare tomorrow at breakfast. He is always expecting to see some truth that he has never seen before. --Chesterton
Sober Inebriation:
http://soberinebriationblog.blogspot.com/