Notes for Descartes’ Meditation I

 

I. Descartes announces that he is after a solid (non-circular) justification for, among many other things, our belief in God. In fact, he is seeking to provide a solid grounding for all of our knowledge.

So what is solid justification? In Descartes’ eyes, the justification of knowledge proceeds on the model of Euclidian geometry:

(1) Begin with fundamental axioms, which are supposed to be self evident and irrefutable.

(2) Then, using self-evident deductive principles, one deduces the rest of our beliefs.

A lot then depends upon our being able to identify these fundamental axioms, from which the rest of ourrknowledge is supposed to derive. This is the search for a foundation of knowledge.

 

So how should such a search go? Here Descartes introduces his "Method of Doubt." The method is guided by the idea that something belongs in the foundation of knowledge only if it cannot reasonably be doubted. So we proceed by subjecting our beliefs to systematic doubt. What survives belongs in the foundation of knowledge.

 

II. A little historical background: Descartes was writing during a time of great intellectual ferment. Scientists had begun to use mathematical techniques to challenge deeply held and cherished common-sense intuitions. For example, Galileo and Kepler had used mathematical calculations and precise observations to argue that, appearances to the contrary, the sun does not move around the earth. Despite what common-sense experience tells us, the earth is not at rest, but rather spinning around like a top at tremendous velocity. Descartes was on the side of the scientists, who were attempting to challenge these deeply entrenched (often theologically backed) views. To do so, Descartes thought that he needed to instill a healthy distrust of sensory beliefs.

An empiricist believes that beliefs from the senses ought to belong in the foundation of knowledge. Descartes’ chief aim in this meditation is to show that the empiricist is mistaken.

The Master Argument against empiricism:

(1) Something belongs in the foundation of knowledge only if it cannot reasonably be doubted. (the Method of Doubt)

(2) Beliefs coming from the senses can reasonably be doubted.

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(3) So sensory beliefs cannot serve in the foundation of knowledge. (Anti-empiricism)

 

 

III. The bulk of the first meditation is spent defending premise (2) of the master argument above against potential challenges from empiricists:

(1) We shouldn’t bother investigating our beliefs our beliefs one-by-one (that would take too long and be much too tedious). Rather, we should treat sensory beliefs as one single giant class.

(2) The senses have sometimes deceived us.

(3) We shouldn’t trust those beliefs that come from sources that have sometimes deceived us.

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(4) So we shouldn’t trust any of our sensory beliefs.

 

An empiricist would likely resist contention (1) above. While it is certainly reasonable to claim that our senses sometimes deceive us, there are specific types of sensory beliefs for which it is unlikely we are deceived:

Empiricists’ first reply: "Well, maybe that’s true of sensory beliefs that are far away or hazy, but that wouldn’t be true of sensations of things "up close and personal"-- that I am here in my chair by the fire, that I am in class right now, that I have a hand, etc."

 

Descartes’ Response (The Dream scenario): Even your sensory beliefs about things "up close and personal" could be mistaken. Some of your most vivid dreams, for instance, might have involved things up close and personal that you swore were real, at least while you were asleep. There is simply no way to tell by experience that you are now only dreaming of sitting in a chair by a fire.

 

Empiricists’ second reply: "Well that might be true of particular things (about what I’m doing now). But what about the general or basic things out of which our dreams are made. How could I have gotten the very ideas of redness, persons, or cats, if these things didn’t really exist? Or how about claims about the very general nature of things: that squares have four sides, that eyes are for seeing, or that 2+2=4? Surely these couldn’t be mistaken, if I am to have these ideas at all!

 

Descartes’ Response (The evil demon scenario): Actually, it is possible to doubt even these most general things. Consider the possibility that an evil demon is systematically deceiving you at every possible turn. There are no cats; the demon is only implanting in you sensory impressions of cats (much like the machines in the Matrix movies feed you systematically false impressions of a thoroughly made-up world). The demon might even cause you to miscount the sides of every square you envision, leading you to suppose mistakenly that squares have four sides. Surely, once we consider this hypothesis, ALL of our sensory beliefs can be thrown into question!

 

IV. Concluding Thoughts on Meditation I: Notice the subtle slide in the meditation. It goes from what might reasonably doubted to what could possibly be doubted. A more sophisticated empiricist might well reply that while one could possibly doubt fundamental beliefs, such as the existence of persons or 2+2=4, it simply isn’t reasonable for one to do so. Nor might it be reasonable for one to seriously consider such fantastic hypotheses as the evil demon or dream scenarios. Indeed, we tend to think of people who entertain matrix-like hypotheses seriously to be completely loony.

Indeed, an empiricist might ask, from where do we discover that our sensroy beliefs are mistaken? From yet other sensory beliefs, of course, which we then take to be correct. The point is that in order to challenge any particular sensory doubt, we might need to take at least some of our other sensory beliefs at face value. So while it might be true that none of our sensory beliefs are wholly immune to challenge or doubt, it need not follow that we can cast them all into doubt at once!