We often attribute 'understanding' and other cognitive predicates by metaphor and analogy to cars, adding machines, and other artifacts, but nothing is proved by such attributions.
I want to block some common misunderstandings about 'understanding': In many of these discussions one finds a lot of fancy footwork about the word 'understanding.'
An utterance can have Intentionality, just as a belief has Intentionality, but whereas the Intentionality of the belief is intrinsic the Intentionality of the utterance is derived.
Our tools are extensions of our purposes, and so we find it natural to make metaphorical attributions of intentionality to them; but I take it no philosophical ice is cut by such examples.
There are clear cases in which 'understanding' literally applies and clear cases in which it does not apply; and these two sorts of cases are all I need for this argument.