@Neoclassical: In the example you gave you already assume a priori. You assume causality as an example. And you assume all the other rules and boundries of the human mind. For example, as an empiricist concerning the natural sciences, I am of the opinion (as I think you have said previously you are too) that causality is not a given and that maybe something other law is in place, etc. The point is, to make any assertion and not contradict ourselves in our limited human reasoning, we have to assert that the law of causality is in place, otherwise we could not make an assertion like you did about the replicators competing in a closed environment for scarce resources. For that assertion we also use no empirical data, simply other prediction than the more adaptive ones outcompeting the less adaptive ones would make no sense to us, we could not make that statement without contradiction. We have it easier with praxeology.
Yes, we do have to make a few certain empirical observations (for example that other humans act rationally and have the same logical boundaries as we as individuals do), but besides those very basic ones that at least I consider to be acceptable (since if other humans didn’t act rational and other truths that I simply have to accept to, well, live my life but can’t know 100%ly for certain since I can know nothing with 100% certainty, basically all knowledge that I’ve acquired is useless to me anyways), I know a priori knowledge and praxeology implications to be true (again, Mises wasn’t talking about absolute truths, which he repeadetly states in HA, but as close to that as a human notion can be).
If they were untrue, which, I admit, is a possibility, then either the few empirical observations that I have decided to accept as facts (that humans act rationally again as the example) are wrong or my human logic is wrong (a much safer bet than statistics for sure, because they too would be invalid if human logic would be faulty as for example in causality not applying) - in either case, it is the best option that exists for analyzing economics and praxeology, because, firstly, economic and praxeological assertions are not isolable (you cannot really empirically analyze certain aspects of the market empirically without knowledge of the rest like you can with experiments in the natural sciences which you can test in a laboratory independent of almost all other factors) and secondly, there are certain phenomena that play a role in the market that we cannot observe, like choice (I’m not saying free will exists, but, as Grayson already said: “so long as I don’t know how specific external facts produce in a human mind definite thoughts and volitions resulting in specific, concrete acts, the mechanistic approach to studying human society doesn’t do me any good.”) or entrepreneurial profit (as distinct from implicit wages and interest in the income of the Entrepreneur).
Furthermore, even in collecting and analyzing imperical data you are accepting a priori knowledge as basis; as said above, without causality or things like “the same physical object cannot be at two places at once”, etc, you could not make the assertion that the statistics of past happenings collected by humans with a limited logic are in any way relevant to future happenings.
Edit: Oh, looking back at my post it seems like I really have gone off-topic with this one
- Well, I really like the methodological dualism as an Austrian insight, too 