Some people intuitively feel like determinism creates a situation where nothing matters, all choices are 'interchangable' or equally 'rational', because 'rationality' means nothing in a deterministic world.
I personally don't agree, because I see 'rationality' as an algorithmic tool, and that algorithm doesn't rely on true indeterminism to be effective. I don't think indeterminism does, or even can, add anything of value to human existence (I accept the very real possibility that we are in fact in a somewhat-indeterministic universe). In the same way that one knife may be sharper than another one, and thus better at cutting - even in a deterministic world - one mind may be more rational than another one, and therefore better at... whatever rationality is good for. Decreasing our chances of being terribly wrong? I don't know.
