Praxeology, Synthetic Apriori

From: Max

Sent: Monday, February 21, 2022 9:37 PM

To: [email protected]

Subject: Synthetic A Priori Question

Hi Walter,

My name is Max. I’m an educator/writer from Los Angeles, I’ve been a libertarian for about 10 years, and I’m a big fan of your work. I watched the debate between yourself and David Friedman and thought you did a great job. Since then, I’ve been arguing with David on Facebook about his odd views about negative time preference.

While I’d firmly call myself an Austrian, I did start to question something when you were talking about synthetic a priori statements. You gave a non-economic example of “Parallel lines can’t cross,” although this example immediately seemed to me like a regular a priori tautology because the rule of “not crossing” is necessarily contained in the definition of “parallel.” Am I missing something here? Similarly with the building block of Austrian economics, the statement “Man acts” could arguably also be a tautology because I would think that acting is a necessary component of the definition of a human being as it’s being used in such an economic statement. So as you can see, I’m not completely convinced now about whether synthetic a priori’s exist, and I’d love to know where you think I might be going wrong.

I think one of the fundamental ways you defined synthetic a priori as opposed to something like a tautology is that it “tells us something about the real world,” and yet, I think tautologies can also tell us new information about the real world. When we break down a word into different words or phrases, we tend to elucidate meaning (meaning that can enrich our understanding of the world). For example, even a tautology we could agree on, “all bachelors are unmarried,” gives us information about the real world to those who don’t already know what a bachelor is. In the realm of morality, I believe we can derive the NAP and property rights from tautological statements about humanity.

I hope this rant doesn’t seem too abrasive. I’m still a big fan, and right now, whether I believe synthetic a prioris exist or not, I still think Austrianism and praxeology itself are sound.

Hope your semester is going well and even if you don’t have the time to answer, thank you for taking the time to read this.



From: Walter Block <[email protected]>

Sent: Monday, February 21, 2022 10:18 PM

To: ‘Max

Subject: RE: Synthetic A Priori Question

Dear Max:

Not abrasive at all. If abrasive, then abrasive is a good thing!

I might be wrong on parallel lines. I’ll have to think about that one.

Yes, tautologies tell us a little bit about the real world: but only how we use language.

Whereas, in sharp contrast, synthetic aprioris tell us much more than mere definitions. I don’t think “man” is defined as being an “actor.” Man is just a species. Ants, too, are a species, and, yet, I don’t think they act, choose, etc. Rather, they are driven by instincts. A straight line is the shortest distance between two points does more than tell us how words are defined. Even David Friedman is confused on this issue, thinking it has something to do with Euclid. The minimum wage creates unemployment for workers with productivities specified by that law certainly says more than how words are used.

Best regards,



5:06 pm on February 22, 2022