Because the only reason you have to believe anything at all is that you perceive things. And the things that you perceive probably lead you to believe things like that you are a human being, that you exist in a particular subset of three-dimensional space, that there are other humans that exist in other subsets of that same three-dimensional space, that these other humans move around and do things that can reasonably be described as "saying things" and "writing things", and that the things that these other humans say and write correspond to circumstances in this three-dimensional space that you occupy so that it makes sense, at least in some circumstances, to label these sayings and writings with labels like "true" and "false" to indicate whether the way they correspond with circumstances is a positive or negative correlation, and if you get these labels right it can help you survive and flourish. Likewise, if you get them wrong (and that includes denying what I have just told you) it will greatly diminish your prospects of survival, and evolution will take care of the rest. In short, it isn't circular because if you try to pick a fight with reality, reality will win.
I see where you're coming from, but none of this really means that justifying inductive reasoning through inductive reasoning isn't circular.
Hume himself thinks that inductive reasoning is grounded in "custom or habit", and thinks it's rational to proceed this way---a solution you'd probably agree with.
I suppose the confusion still remains about how empiricism can be self-justifying. You've laid out a case for why it's empirical reasoning is pragmatic, fine, but that doesn't mean that empirical reasoning is grounded in empirical reasoning, even if empirical reasoning is in fact rational. Whether you go with a Humean-style solution or a Popperian solution, it's just still not the case that justifying empirical reasoning through empirical reasoning is not circular.
I'm disputing something very specific. I'm not disputing that empirical reasoning is rational. What I'm disputing is that empirical reasoning is justified by empirical reasoning. This not being circular is not logically related to actual reality. Like, I'm just saying that this doesn't make sense:
1: If you try to pick a fight with reality, reality will win. (Empirical reasoning is evolutionary useful, etc.)
2: Thus, empirical reasoning is justified by empirical reasoning.
2 doesn't follow from 1. I accept 1, and I accept the rationality of empirical reasoning, but I don't accept 2.
No, I'm not confusing them. At worst I'm using evolutionary epistemology to justify empiricism. And I'm only doing that because I'm presenting an informal argument. I can justify empiricism without resorting to evolution. But invoking evolution has more emotional appeal to entities that have evolved and so presumably don't have to be persuaded of the value of survival.