In Part One of his Discourse on Method (I’ll spare you the full 16 word title), Descartes presents his intellectual autobiography. He describes all the subjects he studied in school, noting their advantages and disadvantages. This, in itself, is an interesting read, especially if you have ever found yourself frustrated with school, for the “disadvantages” are blunt and memorable: studying other cultures? travel instead; poetry? it can’t really be taught; history? it leaves out important details; philosophy? it just enables you to sound smart; and so on.
Indeed, Descartes seems to have experienced these disadvantages of “book-learning” so keenly that at the conclusion of his education (a law degree), he found himself “confounded by so many doubts and errors that it seemed to me that I had not gained any profit.”
At least all those doubts were not accompanied by 100k in student loan debt. But I digress.
Descartes, however, did not use this as an excuse to give up on truth. Rather, he decided to instead seek truth not in books, but rather in “the great book of the world.” Furthermore, this is not just a “knee-jerk reaction” on the part of Descartes, for he also reports a positive reason for his optimism that he would have better luck finding truth in the world. The argument is a little gem, and it is hard not to find one nodding one’s head in agreement:
“For it seemed to me that I could find much more truth in the reasonings that each person makes concerning matters that are important to him, and whose outcome ought to cost him dearly later on if he has judged badly, than in those reasonings engaged in by a man of letters in his study, which touch upon speculations that produce no effect and are of no other consequence to him except perhaps that, the more they are removed from common sense, the more pride he will take in them, for he will have to employ that much more wit and ingenuity in attempting to render them plausible.” (trans. Donald A. Cress)
Now from time immemorial human beings have noticed what an effective motivator self-interest can be in human affairs. But we normally notice this in terms of behavior, as is evident in the following delightful exchange I had with a student last semester:
Student–“Mr. Schimpf, how do you decide when to wear a vest?”
Me–“I don’t know? How do you decide what to wear on any given day?” (Notice what a good philosophy teacher I am, answering a question with a question.)
Student–“Well, if I’m going to see this girl that I have a crush on, I might throw on a Polo.”
Beautiful. Self-interest motivates the choice. If you want other people to dress well or do well in general, show them why it is in their interest. Give them a stake in the matter, some “skin in the game.”
However, notice in that quote above from Descartes that he has made a subtle transfer. This counsel of prudence normally applies to our actions, but Descartes has argued that it should apply to our grasp of truth as well. According to him, we will be best able to attain the truth whenever that truth is a matter of existential importance to us, when the outcome will “cost us dearly” if we misjudge.
The students love it. I love it–even though it contains an obvious dig at people like me. But what I love most about Part One of the Discourse is Descartes’ honesty. For immediately after offering this argument with which everyone naturally agrees, Descartes admits that it just did not pan out that way when he actually went out into the world:
“It is true that, so long as I merely considered the customs of other men, I found hardly anything there about which to be confident, and that I noticed there was about as much diversity as I had previously found among the opinions of philosophers.”
In other words, despite being motivated by our own self-interest, we remain so very stupid. Or maybe we aren’t stupid, but maybe it is just too difficult to figure out which evidence is most important in regard to any particular question; as Descartes had already noticed in the very first paragraph of the Discourse, we all may be equally intelligent, but “we lead our thoughts along different paths and do not take the same things into consideration.” No, even self-interest cannot protect us from our own finitude. The world is just too big for our little minds; there are too many possible pieces of evidence to consider, and so we often fall short of the truth even in the most important things.
Yet all of this is not an argument for despair, but rather just a reason that shows a natural need in our lives for Revelation, for someone to assist us towards the truth. It is not that it is impossible to know anything without some god telling it to us, but as St. Thomas Aquinas noted, our human limitations realistically mean that whatever we could know could only be known “after a long time” (i.e. years of arguments on Facebook) and “with the admixture of many errors” (i.e. “let’s spray DDT on schoolchildren”).
We tend to view divine revelation, such as the Bible and its reflection in the moral teachings of the Church, as an obstacle or a restriction, a “downer.” But in truth, divine revelation is more like an adrenaline shot for our minds.