I agree that intelligence is highly genetic. So is schizophrenia, though, and I don't think anyone would describe schizophrenia as a physical trait. So merely being genetic is not a proof of being a physical attribute.
Just like intelligence and IQ are two separate things, so is intelligence and the underlying biological structures enabling intelligence. Saying the former when you mean the latter is not just unclear, it's flat out incorrect.
There is as much proof of the 100 times intelligence gap as there's for any other number. Which, yes, is zero. Nobody has come up yet with any method to quantify intelligence directly, and until that happens, it'll be impossible to make any objective statement about raw amount of anybody's intelligence. I was just saying what I personally believe to be most likely.
I was wrong about lack of correlation. Thank you for the links. That said, I did dig further, and from what I gathered, brain size differences account for at most 25% of variation in IQ. The other 75% must be either non-physical differences, or physical differences that don't affect brain size. My bet is on the former, because there's neither any evidence nor a theoreticsl model for the latter. Granted, I haven't looked for a theoretical model too deeply; you're more than welcome to prove me wrong yet again.
The biggest obstacle for the ... whatever the thing you're saying is called, I'm 100% sure I'd get it wrong if I tried to name it, so I won't... are child geniuses. Children have smaller bodies, shorter legs, and less muscle mass than adults. There are extremely few 7 year old boys who are taller, faster or stronger than a median 25 year old man - around one in a billion for height, probably zero for the other two. Similar story with head circumference, though to a lesser degree. The 95% range for 7 year olds barely overlaps with the range for adults. Every single case I could find of a child that young reaching the mean HC of an adult man (57cm) was a sad story of a rare medical condition that definitely didn't make them smarter. I use it to conclude it's extremely rare for child heads - and by proxy, child brains - to reach the size of adults. If intelligence was physical, that should also prevent virtually all children from being more intelligence than a median adult. And yet, there's plenty of children whose intelligence surpasses most adults. It's almost commonplace. How do you reconcile that with your argument?