epwripi: This might sound cockier than I mean it to, but really, I tire of such assertions. I know what intelligence is, and I suspect many here do as well. Plenty of good definitions have been put forth, but somebody is always going to have a nitpick because it doesn't include their favorite metaphor, and there are always going to be people who don't want it to be defined. It can certainly be quantified roughly and relatively, at the least (though "points on a linear scale" may be tending towards a strawman extreme), and when people speak of an individual's intelligence, it's implied that they're talking about a certain time, or an average over time. It's trivial to point out that individuals can be consistent and inconsistent. It's the same with athletic ability.