Mises’s action “axiom” or false dichotomy?

I've been watching the recent libertarian conundrum - concerning the morality of using taxes to prevent a killer asteroid from wiping out humanity - with great fascination. For anyone not privy to the whole saga... Essentially, some (uber) libertarians have made it plain that they would rather die with their principles than see some thievin' gub'mint send up a Bruce Willis-type into space to blow up any asteroid on the back of stolen tax money. [Side note: I was planning to draw some fun parallels to global warming, but John Quiggin beat me to it.]

Lest it be unclear, I am firmly in the camp that proclaims such positions as absurd. Further, it appears that many self-proclaimed libertarians count themselves in the same boat. I'd be worried if they didn't; it would elevate a cut-off-your-nose-to-spite-your-face mentality to an astronomical level, so to speak. Now, there have since been some more nuanced defences along the lines of: "I would contribute; I just don't think you can force other people into contributing." However, from my perspective these positions still overlook the free-rider problem and ultimately equate to little more than a form of culpable homicide. (You can see some of my comments on these issue here.)

All this, however, is just a prelude to what I want discuss here.

Amidst the whole asteroid palaver, I saw an interesting discussion between Daniel Kuehn and Jonathan Catalan. In particular, on why we shouldn't conflate the responses of Austrians with libertarians regarding this matter; even though many Austrians would certainly identify themselves as libertarians, and (I imagine) vice versa. I thought Jonathan's point about these two groups deriving their end-points as the result of distinctly different processes - positive for Austrians vs normative for libertarians - was well made. My interest piqued, I started doing a little internet research to see what else might have been said about the strong link between Austrian economics and libertarianism in spite of their opposing methodologies. Had they been unified through a grand string theory of liberty?

Unfortunately, I got distracted.

And now, finally, we get to the meat of today's post...

A question occurred to me while I was reading a passage by George Selgin, explaining why (many) Austrians hold Ludwig von Mises's praxeological method to be the most valid form of all economic reasoning. Following Immanuel Kant, it basically boils down to a belief that the human action axiom cannot be refuted, because, as per Selgin (pg 22):

To meaningfully deny the "action axiom" (i.e., the claim that people act purposefully) is difficult. Denial of the axiom's empirical validity involves a purposeful act on the part of skeptics. It therefore confronts them with the uncomfortable choice of either conceding the issue or proclaiming that their own disagreement is purposeless. Thus, any denial of the action axiom is self-contradictory.

Am I the only that sees an obvious philosophical objection to this? It extrapolates from a single (contrived?) instance and purports to have shown that the same rules must hold for all human actions over all of time. Near as I can tell, this is done without further justification.

To put things differently, just because I act purposefully at this one particular moment in time (i.e. by denying the action axiom), how does rule out the possibility that I may have acted in a non-purposeful way at any other moment? Indeed, I would think that if someone did try to deny the action axiom, their position would very likely be based on past events and experiences that are completely independent of the present “catch-22” moment. You could easily argue that framing things in such a way – to assume that people act must purposefully at all times, or not at all – is a false dichotomy that invalidates the claim to (strict) apodictic truth.

At best – or worst, depending on your position – it therefore seems to me that denying the action axiom is only momentarily self-contradictory, not an exhaustive set that is valid over all time.[*]

A rather laboured analogy [slightly adapted to make things a bit clearer- Ed.]:

MARIO: "Hey Luigi, are you awake?"
LUIGI: "No."
MARIO: "A-ha! But you have to be awake, since you just answered me. So... Proof that you don't sleep!
LUIGI: "Huh?"
Etcetera.

Anyway, this seems such an obvious objection to me that I can't shake the feeling that a) someone has already proposed it (to possible counter-argument), or b) I'm wrong in an even more obvious way. So, followers of Mises: Hit me with it! 

OTOH, if there is merit to my argument, then I imagine that it opens up the possibility for Austrians, on philosophical and logical grounds, to at least engage in empirical testing of their theories and thus expose them to the scrutiny of falsifiability.

UPDATE: See follow-up here.

Disclaimer: I am in no way disputing the argument that the people generally act with the purposeful intention of improving their situation... i.e. the benefits of voluntary trade, etc. Indeed, I take this to be one of the fundamental pillars of economics and, despite his novel application, Mises was hardly the first to suggest it.(I'm not suggesting that he made this claim.) What I am trying to establish, however, is whether we can truly and with universal certainty describe "human action" as an apodictic axiom, when the key defence rests on a flitting moment of self-contradiction under very specific circumstances.

___

[*] Compare Decartes’s epiphany: “I think therefore I am”. I regard this as a valid synthetic a priori fact (a la Kant), precisely because it concerns only the present moment, i.e. “I am”.