 First, insofar as philosophy and psychology are concerned with the nature of mind, they aren’t in the least trammeled by the presupposition that mentation consists in computation. AI, at least of the “Strong” variety (we’ll discuss “Strong” versus “Weak” AI  below)  is indeed an attempt to substantiate, through engineering certain impressive artifacts, the thesis that intelligence is at bottom computational (at the level of Turing machines and their equivalents, e.g., Register machines). So there is a philosophical claim, for sure. But this doesn’t make AI philosophy, any more than some of the deeper, more aggressive claims of some physicists (e.g., that the  universe is ultimately digital in nature)  make their field philosophy. Philosophy of physics certainly entertains the proposition that the physical universe can be perfectly modeled in digital terms (in a series of cellular automata, e.g.), but of course philosophy of physics can’t be identified with this doctrine. 