Not at all. [MENTION=97077]iserith[/MENTION] isn't saying that the frog can't take the IQ test because of its INT score. Presumably, in iserith's game, a PC with a 2 INT can sit an IQ test.
Iserith is saying that the frog can't take an IQ test because it's a frog.
I made the same point about the giant lizard. It's a lizard. And therefore, for any number of reasons - its lack of cognitive skill, its lack of hands - it can't pick locks or use chopsticks. The fact that its DEX is rated at 12 has no bearing on these matters.
Which only goes to tell us that stats like INT and DEX don't exhaust our understanding of the cognitive and manipulative capabilities of a creature. We know that already because we know what frogs and what lizards are.
All the 12 DEX of the lizard is doing is telling me how to generate some necessary mechanical details for the creature (init, AC, etc).
All the 2 INT of the frog is doing is telling me that it can't escape from a maze spell.
Or let's take the giant ape, with an INT of 7. It can't speak, or read and write, or count, or solve crosswords puzzles. Does that mean a PC of INT 7 can't do any of those things either? To me it is obvious that those limitations on a giant ape are not consequences of it having an INT of 7, but consequences of the fact that it is an ape, not a human (or near-human) being. And I'm pretty confident that [MENTION=97077]iserith[/MENTION] agrees with me on this point.
Absolutely!
For instance (and unlike earlier editions of the game), 5e doesn't link the INT score to language learning. Hence, whatever exactly is meant by saying that INT measures recall and memory and reasoning, it clearly doesn't measure all of those things, because the game permits a PC to have a low INT yet know many languages. (Per the Basic PDF p 68, the training takes 250 days regardless of INT.)
Nor does INT place any limitation on tool proficiency. It is possible, for instance, to be a master lockpick with 3 INT.
So obviously INT does not encompass everything even within the domains of reasoning and recall, let alone other aspects of what would ordinarily be called intelligence.
The rules text actually says that INT measures the ability to reason (among other things - obviously it's possible for a human being to have poor reasoning but good memory, and it's not clear how exactly this impacts on the INT score). What form does the measure take? As I read the rules, it primarily takes the form of imposing a penalty on ability checks made to determine the outcome of feats of reasoning.
For instance, an INT check would presumably be made to find out how look it takes a PC to solve a crossword puzzle, or to see how far s/he can get (assuming that the GM hasn't actually drawn up a crossword puzzle for the players to solve). A character with a low INT would suffer a penalty, and hence be less likely to succeed at the crossword in a given amount of time. To me, that seems to be the main respect in which INT is a measure of reasoning ability.
