The Role of Global Doubt in the Search for Knowledge

Ever since Descartes, Global Doubt has been a tool used off and on by many philosophers. Some think that it is too strong, that it leaves nothing for us to be certain of. Others, like myself, believe it is necessary, that through it we can establish absolute certainty in a small number of things. True knowledge implies the impossibility of being wrong. In other words, it can't be doubted. Are there any such things? I say yes, and I put forth as examples the following: the existence of the Self ("I think, therefore I am"), pure mathematics, and pure logic.

Doubting such things as these seems totally incomprehensible to me. Without the existence of the Self, the word "I" has no meaning. The phrases "I think" or "I see" or "I do" degenerate into nonsense. Doubting the "I" seems almost childish to me. It is akin to saying "But how do you know?" to every statement uttered without bothering to reflect on the statement to ascertain its meaning. Likewise, doubting simple mathematical claims such as 1+1=2 seems equally silly. There is actually a mathematical proof for 1+1=2, but I believe it is unnecessary. I understand what is claimed, and I apprehend the necessity of its truth. I don't need further convincing. Finally, there are the claims in pure logic: "All humans are mortal. Socrates is human. Therefore, Socrates is mortal." What is claimed is clear and precise; I comprehend it and see the necessity of its truth. And again, I don't need further convincing.

That said, it would be a great disservice to the discussion to fail to point out the one major drawback of absolute certain knowledge. It is uninteresting. It is dull. No one cares about simplistic math or logic, or even the nature of the Self. If we limit ourselves only to the knowledge of which we are certain we will have an extremely myopic view of reality, indeed. I cannot stress that enough. True, certain, absolute knowledge exists, but its scope is so limited that by itself it is woefully inadequate to the task of dealing with life.

But it does serve a purpose. The Self helps us comprehend others and the world through language. Mathematics and logic are applied to the natural world through science. Science, though it does not produce pure theoretical knowledge (as a result of Global Doubt) it does produce the next best thing: well-founded rational beliefs. Well-founded rational belief differs from true knowledge because it is not 100% certain. However, it also differs from mere opinion or guess-work because it is backed up by argument and evidence. It exists somewhere in the realm between opinion and knowledge-the more evidence it has to support it, the closer it is to knowledge. Well-founded rational belief also gives us something math and logic alone cannot: know-how. The difference between knowledge and know-how is this: knowledge answers the why of things, it gives us the full nuts and bolts explanation; know-how gives us the how of things, it allows us to apply our knowledge or our rational belief to accomplish tasks such as building things, or controlling our environment for our own benefit, etc...

Another reason that absolute knowledge is so limited and will never give us a complete accounting of the world is, in a word, fuzziness. Many things are not black and white in this world, there are many shades of grey. We see this in many modern and emerging disciplines. Quantum mechanics is one the more obvious examples where a fuzzy indeterminacy is built into the Heisenberg Uncertainty Principle. Likewise, in computer science, the field of fuzzy logic is developing to handle non-discrete truth values. And finally, in some of the more advanced mathematical disciplines it has been shown that some proofs are impossible to give via Godel's Incompleteness Proof. For example, in transfinite set theory we know that the infinite number aleph null exists and is smaller than the infinite number 2^aleph null, but we do not know if there is an infinite number between the two.

If one takes nothing else away from this essay, take away at least this: There is certain-but-limited knowledge, baseless opinion and well-founded, rational belief. And as far as humanity's eternal quest for "knowledge" and perpetual struggle for survival are concerned, well-founded rational belief is where the action is.