Hello Michael and Steve,
I suppose I'm an empiricist, but I'd be more inclined to say "all
sentences are empirical" to escape your trap. I'm sure one of you
can lump me in with some school of thought along those lines. 
Every word is a snippet of human behavior; every sentence you
utter is the result of lifelong experience. I only know that "one
plus one equals two" is true because I learned the meanings of
those words through experience.
But such an empiricism doesn't reduce my unwavering belief in the
efficacy of logic or lead me to some kind of relativistic bollix;
I firmly believe that A is A, one plus one equals two, etc., etc.,
and I will join you in ridiculing anyone who doesn't.
That said, I don't believe that "individuals act exclusively in
ways they perceive will make them better off" unless I define
those words in ways I consider to be overly simplistic; and even
if it is true, the implications for economics are far from
tautological. To understand how people act -- or that they act at
all -- I must observe them acting, and to understand how they will
act in groups I must observe them acting in groups.
Cheers,
Justin
A while ago, Michael Edelstein wrote:
The Austrian point here is that essential economic truths are
not the subject of empiricism, but rather are synthetic a priori
truths, e.g., "man acts," "individuals act exclusively in ways
they perceive will make them better off," etc.
http://www.mises.org/esandtam/pes2.asp
To which Steve Dekorte replied:
It seems to me that:
"What does this first step in our criticism of empiricism prove?
It proves evidently that the empiricist idea of knowledge is
wrong, and it proves this by means of a meaningful a priori
argument."is a straw man argument as empiricism (or at least the logical
positivism of Ayer) does not deny the a prior - it just limits
it to tautologies, of which the definition of empiricism is one
(that experience is experience, and non-experience is not).
After which Michael Edelstein queried:
Consider the sentence: "All sentences are either empirical or
tautological." Is this sentence empirical or tautological?
At which Steve Dekorte retorted:
It's an analytical proposition that is non-tautological. What is
the point of your question? Are you confusing the a priori with
all analytical propositions?
To which Michael Edelstien reacted: