The strength of a theory is not what it allows, but what it prohibits; if you can invent an equally persuasive explanation for any outcome, you have zero knowledge.

If our extinction proceeds slowly enough to allow a moment of horrified realization, the doers of the deed will likely be quite taken aback on realizing that they have actually destroyed the world. Therefore I suggest that if the Earth is destroyed, it will probably be by mistake.

In our skulls, we carry around 3 pounds of slimy, wet, greyish tissue, corrugated like crumpled toilet paper. You wouldn't think, to look at the unappetizing lump, that it was some of the most powerful stuff in the known universe.

[...] intelligent people only have a certain amount of time (measured in subjective time spent thinking about religion) to become atheists. After a certain point, if you're smart, have spent time thinking about and defending your religion, and still haven't escaped the grip of Dark Side Epistemology, the inside of your mind ends up as an Escher painting.

The obvious choice isn't always the best choice, but sometimes, by golly, it is. I don't stop looking as soon I find an obvious answer, but if I go on looking, and the obvious-seeming answer still seems obvious, I don't feel guilty about keeping it.

When something is universal enough in our everyday lives, we take it for granted to the point of forgetting it exists.