Descartes on Atheism
As anyone with anything more than a passing acquaintance with early modern 
philosophy knows, René Descartes rather famously enlisted the help of God to guarantee the validity of his perceptions (for God would not be so cruel as to deceive us). But did you ever consider what the consequences of this solution would be for non-believers? Obviously, they’re going have problems establishing the veracity of their sensory perceptions. As certainty awaits proof of the deity’s existence, atheists are, it seems, doomed to Cartesian scepticism. They simply have no way of knowing they are not deceived by what they see.
Descartes, however, thinks that the problem goes even deeper:
That an atheist can know clearly that the three angles of a triangle are equal to two right angles, I do not deny, I merely affirm that, on the other hand, such knowledge on his part cannot constitute true science, because no knowledge that can be rendered doubtful should be called science. Since he is, as supposed, an Atheist, he cannot be sure that he is not deceived, in the things that seem most evident to him, as has been sufficiently shown; and though perchance the doubt does not occur to him, nevertheless it may come up, if he examines the matter, or if another suggests it; he can never be safe from it unless he first recognizes the existence of the God.1
Descartes says much the same thing in the Fifth Meditation:
…if I were ignorant of the facts of the existence of God, and thus I should have no true and certain knowledge, but only vague and vacillating opinions.2
The limitations on atheists’ knowledge do not stop with merely validating sensory perceptions. It is only after one recognizes that there is a God that one achieves ‘true and certain knowledge’; that is, knowledge of all ‘eternal truths’ (by which Descartes means a priori and innate truths). Hence, even in regard to mathematical or geometric truths the atheist may still be deceived. Atheists, then, are denied not only certain knowledge of the external world, but also knowledge of mathematics and all ‘eternal truths’. Ouch.
Meanwhile, if anyone could help me solve the following conundrum I’d appreciate it: I’ve been staring at the shape to the left for the past few hours, and though the interior angles appear to add up to 360°, I’m just not sure…
CITATIONS:
1. René Descartes, “Reply to Objections II,” in The Philosophical Works of Descartes v. 2, eds. and trans. Elizabeth Haldane and G.R.T. Ross, Cambridge: Cambridge U.P., 1970, p. 39.
2. René Descartes, Meditations on First Philosophy, in The Philosophical Works of Descartes v. 1, p.183.
Comments
7 Comments so far
You almost got me with the parallelogram question! That was very funny.
BTW, Maybe there is something to the Descartes point (OK, not much, but still…), because lot of naturalists will accept Quinean thesis that anything is revisable (even principle of non-contradiction) in the light of new experiences.
Sure, laugh it up! Meanwhile, I’m lost in the dark with an imperilled soul, not knowing an isosceles from my assh….
“God wouldn’t decieve us!”
“What about crazy people? Or the blind? Or…”
I have no idea why Decartes thought it was such a good answer. Maybe he just got payed by the church and had to come up with yet another reason to be a theist…
I think the question Descartes was really raising was “why do I believe that my perceptions give me knowledge? how do I know the world isn’t just constructed in such a way that I can’t really know it?” Perhaps he wrestled with the question himself and, being a theist, arrived at the conclusion that God would not be so cruel as to construct the world in such a way. It’s not a giant leap from that point to wonder how an atheist justifies the belief that his perceptions are reliable without a similar principle to fall back on.
About the parallelogram: when you lengthen the horizontal lines, I can prove you that the interior angles are 360 degrees
Typo – ‘Obviously, they’re going [to] have problems establishing the veracity of their sensory perceptions’.
Of course, as many contemporary philosophers will agree, any epistemics that are derrived ‘a priori’ can not be accepted as an irrefutable statement, especially one which entails the existence of God. If anything, it serves as a delightful notion of how, during the enlightenment, Descartes and his band of Rationalist and Christian familiars viewed Atheists. Not only is their an evil deciever, deceiving everyone on the planet to think that up is down, a square is a circle and my right foot is in fact my mouth – Now God is deceiving me and denying me the truth because I read too much Neitzsche? Jeez, He’s fickle.