I don’t believe in anything with absolute certainty; I always allow room for doubt. How much doubt, though, depends on the type of statement:

Level 1 – Least doubtful

In my opinion, Descartes uttered the least doubtful statement ever: “I think, therefore I am.” I’d have no sense of self without making this assumption, so I definitely couldn’t inquire about anything else.

Level 2

Next, I consider some math axioms to be very certain: identity, transitivity, etc. As an example, here’s a typical level 2 statement: “1+1=2”.

I don’t fully understand a lot of math axioms, though, so I relegate them to more doubtful levels. More competent mathematicians will be able to include more math axioms in level 2.



Level 3

My personal choice for a level 3 statement is: “My senses reveal an external reality, governed by objective laws, which exists independently of conscious minds.”

Specifically,

The colored shapes that I see represent objects with existences of their own, and those objects don’t disappear when I turn my back on them.

The objects that I can sense are governed by consistent, implacable laws. People can’t, for example, wish for food to appear in front of them because the laws of nature don’t allow it.

These laws are not relative. Other people inhabit the same reality that I do, though admittedly they may perceive it differently (as in the case of colorblindness).

It’s important to note that I could be plugged into The Matrix or my senses could be faked in some other manner. While I acknowledge this possibility, I can’t see how any productive search for knowledge can take place without assuming that an objective reality exists, and that my senses are mostly accurate.

It was a long time before I realized that the strongest version of this statement (which I no longer endorse) implicitly assumes that omnipotence is impossible. That’s because literal omnipotence requires total control over reality, not just advanced technology that works within the laws of physics to create the illusion of omnipotence.

I believe that many monotheists reject this “strict” statement, and instead make a different assumption at this level. That is, monotheists seem to assume that God exists and has absolute control over a reality that is ultimately not objective, in the sense that mechanistic laws don’t always hold true (otherwise “genuine” miracles would be impossible). Depending on their particular theology, some monotheists seem to agree that reality usually appears to be governed by objective laws, but account for this by saying that God isn’t capricious.

I think this implies that monotheists accept a different version of the objective reality assumption. It’s probably something like “God exists, and when He isn’t performing miracles, He allows reality to appear as though it’s governed by objective laws.” At least, that’s my best guess. Any monotheists want to comment on this point?

Level 4

Various scientific theories go here. Science isn’t supposed to provide truth, it only provides models which predict experiments and observations. The theory with the fewest axioms that most closely matches the evidence wins. (At least until a better theory comes around.)

As a result, scientific statements always have room for doubt.

Level 5

Most knowledge regarding human history belongs here:

I’m suspicious of historical evidence because many people have had motives to slant the “official” story in their favor.

Depending on how old the story in question is, there’s also been a lot of time in which to alter the evidence.

Research shows that humans are prone to developing “false memories.” Since history is often nothing more than recorded memories, I’m skeptical of historical claims even if I completely trust the person making the claim.

Historians also have to somehow correct for years of detritus laid over the evidence by humans who– even if they’re not malicious– are still less predictable than animals or geological processes.

Also, history is the study of a subject that’s simply too emotionally charged– all of us have our own cultural reasons for believing in one version rather than another.

That’s not to say that scientists aren’t biased in favor of their own pet hypotheses. It’s just that scientists’ biases seem more geographically random than historians’.

Level 6 – Most doubtful

Any statement which can’t be falsified or checked for internal consistency goes here. These statements might be correct, but there’s currently no way for me to tell!

Most of political theory, psychology and sociology goes here, in my opinion. Along with a lot of philosophy and most religious statements.

Last modified February 6th, 2012