People love talking about intelligence but I'm yet to see a measurable definition. The best anyone can manage is "you know it when you see it" (like porn). Am I missing something or is this all just a dark road to an unknown destination (possibly just a dead end?)
The value of definability is moot at best imho. "Mathematics" is also not easy to define, there are volumes philosophers of mathematics discussing this, some even say "mathematics is what mathematicians find interesting" (similar to your porn example) but this doesn't stop us from studying mathematics. Same goes for science e.g.. People like Popper or Kuhn spent a lot of mental cycles arguing what is and what is not science, yet people still do science every day without reading them.
In some ways this way of thinking is too meta. In order to be a good mathematician, it is not necessary to understand the nature of mathematics from an outside perspective. This view can be very useful e.g. if you're working on foundations, but that doesn't mean before being good at mathematics one must be good at understanding the nature of mathematics. That seems like the job of philosophers, not mathematicians. (Well, sometimes the set has intersections, e.g. Brouwer, Hilbert, Godel and Penrose (theo. physicist) wrote some works on phil. of math).
EDIT: To express this slightly more formally: in order to understand a theory of a model, you do not need to understand the model comprehensively. You can be an expert in intelligence science by studying the falsifiable and predictive theories of intelligence science without understanding the nature of intelligence itself.
> Same goes for science e.g.. People like Popper or Kuhn spent a lot of mental cycles arguing what is and what is not science, yet people still do science every day without reading them.
I'm quite fond of a terrible mathematical joke which this reminded me of.
"I'm worried about my nephew, I was trying to teach him to add numbers, but he can't even pronounce zermelo fraenkel set theory, how's he ever going to learn it?!"
This goes hand in hand with a functional definition of knowledge, where we judge whether a system or an agent "really knows" something through measuring success or failure in a variety of scenarios where knowing that thing (and properly applying that knowledge) is necessary to make an effective decision. Or, quoting Forrest Gump, stupid is as stupid does.
