Powell critiques J.C. Lester’s argument tha critical rationalism is the basis of libertarianism.

Aaron Ross Powell
Director and Editor

Aaron Ross Powell is Director and Editor of Lib​er​tar​i​an​ism​.org, a project of the Cato Institute. Lib​er​tar​i​an​ism​.org presents introductory material as well as new scholarship related to libertarian philosophy, theory, and history. He is also co‐​host of Libertarianism.org’s popular podcast, Free Thoughts. His writing has appeared in Liberty and The Cato Journal. He earned a JD from the University of Denver.

I want to start by thanking J. C. Lester for joining Lib​er​tar​i​an​ism​.org as a guest blogger. His ideas are provocative and worth discussing, as is obvious from his first post. Here I’d like to briefly raise two questions I have about how he applies Popper to libertarianism. The first deals with the system for falsifying theories. The second is about the strategic value of critical rationalism.

Can Libertarianism Be Falsified?

The basic idea of falsification is that a theory cannot be proved (there could always be some piece of evidence waiting out there that would contradict it) but it can be falsified (a piece of evidence is found that contradicts it). If critical rationalism applies to libertarianism, it must be true, if nothing else, that libertarianism is subject to falsification.

What would that look like? Does libertarianism make predictions that are subject to falsification? It’s true that free market economics makes predictions. We might say that a policy of protectionism will harm our own economy. If protectionism turns out to not harm the economy, then (that principle of) free market economics is falsified.

But Popper fully admits that, given the fallibility of humans and the instruments they use to examine evidence, we probably shouldn’t toss out a theory based on a single piece of contradictory evidence. After all, the evidence might be bad. We might have read our meter wrong. And so on. We shouldn’t give up on a theory too easily, in other words.

So it’d take more than one instance of protectionism working before we throw Adam Smith and Bastiat out the window. The trouble might be, however, that this wiggle room proves too much—that, when we’re talking about theories like libertarianism or socialism or free market economics or protectionism, there’s just no way to come up with the kind of evidence needed to pronounce something false.

Take the stimulus. Clearly the impact of it counts as evidence against economic theories. But evidence of what? And against which theories? Paul Krugman might argue that the stimulus failed to spark the kind of growth we hoped because it wasn’t big enough—and had it been smaller, we’d be in much worse shape than we are. My Cato colleagues, on the other hand, might argue that the stimulus never could’ve worked in the first place, and so it was, by definition, too big. Furthermore, each side is perfectly capable of modifying their underlying theories to allow even fully interpretable evidence. Maybe there was something really special about this particular time for stimulus that made it not work when it otherwise would, or work when it otherwise wouldn’t.

These sorts of questions become even more difficult to deal with when we’re talking about abstract political philosophy ideas like liberty or equality. If I adopt a high liberal position, for instance, and do so because I value equality over liberty, what sort of evidence might prove me wrong?

Spreading Liberty without Arguments

This brings me to my second concern with critical rationalism as the basis for libertarianism. Simply put, what motivates non‐​libertarians to listen? It seems at least plausibly rational for high liberals, communitarians, or conservatives to say, “Sure I haven’t disproved your theory, but you haven’t given me any reason to believe it, either.”

Put another way, does critical rationalist libertarianism rely upon libertarianism being the default position within political philosophy, one that must be proved wrong before we’re justified in believing anything else? If it does, that seems like quite a hurdle in getting non‐​libertarians to accept it.