Francis Fukuyama reviews Bruce Caldwell's recent book on F.A. Hayek for the Wilson Quarterly, emphasizing Hayek's hostility, not merely to state economic planning, but to empirical social science in general. It's nice (if a little rich) to see the man who once confidently declared the "end of history" acknowledging the unpredictability of emergent orders. But the critique actually seems too strongly put. It's doubtless true that we can't expect to "fully model" a system, like the market or a human culture, whose "higher functions cannot possibly be inferred from its physical substratum." But the impossibility of a "full" model in that sense, while probably a good reason to be wary of attempts at intervention, scarcely seems to make the case against positive social science per se. After all, complex physical sciences like organic chemistry don't proceed by straight deduction from the laws of particle physics. And increasingly sophisticated econometric and statistical tools make it possible to control for more and more confounding factors. That doesn't mean we can plan economies, but we're not confined to ignorance either. Which is a good thing, because many of the most potent arguments for free societies rest on the very measurable benefits they produce.