Foundation of all Knowledge

by PDS

In part one of Descartes’ Mediations, the famous philosopher embarked on a method of systematic doubting. Every belief that could be doubted, for any reason at all, was dispensed with. Descartes refused to affirm even beliefs that seemed to be obviously true – a task which he found he struggled to do. To help him systematically doubt even these beliefs, he imagined a supremely powerful demon who was deceiving him at every point. Using this tool, Descartes even manages to doubt that he knows simple mathematical beliefs such as two plus three equals five.

While this leaves Descartes in a state of discontent, nonetheless, he presses on:

I will, nevertheless, make an effort, and try anew the same path on which I had entered yesterday, that is, proceed by casting aside all that admits of the slightest doubt, not less than if I had discovered it to be absolutely false; and I will continue always in this track until I shall find something that is certain, or at least, if I can do nothing more, until I shall know with certainty that there is nothing certain.”

Descartes is determined to believe nothing unless it cannot be doubted, even if these leaves him with no knowledge at all.

But no matter how much Descartes doubts, he cannot doubt one thing: “So that it must, in fine, be maintained, all things being maturely and carefully considered, that this proposition (pronunciatum ) I am, I exist, is necessarily true each time it is expressed by me, or conceived in my mind.”

Even while Descartes doubts, the very fact that he is doubting proves to himself that he must exist. It is this truth: “I am, I exist” that Descartes builds his knowledge on.

In the search for knowledge, then, we have seen three different approaches to knowing that which is, the stable objects of knowledge. For Plato, knowledge is by recollecting pre-existing knowledge; for Aristotle, knowledge starts with sense perception; for Descartes, knowledge starts with what is indubitable – that is, what is impossible to doubt.

A lot more could be said about each of these Philosopher’s epistemology, but for now these posts will hopefully of provided us with the background for the introducing Joseph Butler’s Analogy of Religion.

Is Descartes’ starting point for knowledge reasonable?