1. The greatest philosophical mistake is to demand proof for the obvious. See Hume.
2. The second greatest philosophical mistake is to try to prove the obvious. See Descartes.
He expands on this a little in a post called The Common Sense of Bayesianism. I think the core of the argument is this:
How do we unseat a common sense claim? Only by using even stronger common sense claims against weaker ones.
I do not have a good response to this, but the idea makes me fidgety. I just don't like it. I want the obvious to be questioned.
But then Mark Kingwell came to the philosophical rescue, as has become a kind of theme lately. These few sentences probably are not enough to make the point, but they come from a longer passage in his book Better Living that made the point beautifully. You'll just have to trust me (or read the book yourself).
Appearing ridiculous means asking questions that seem so silly as to be beyond doubt: Is that a chair I see before me? How do I know anything at all? Can I prove that there is not an elephant in the room? When I sleep, where does my consciousness go?
Voltaire once said, “As for the obvious, leave it to the philosophers.” His comment was meant to capture the common prejudice that philosophers only tell us what we already know or attack questions so clear as to be beyond sane inquiry. It was intended as an insult. It should be, instead, a rallying cry—a challenge to all of us to explore what we are, and perhaps succeed in becoming who we are. Even at the risk of appearing ridiculous.
