It sounded blatantly false, so I looked up the paper; and it seems Taleb might be saying that the road is not simply reversible and that one direction is not just the same as the other. I hope. Because, I mean, really, what do you call a nuclear weapon if not a practical application of theoretical knowledge? Fission weapons did not exist in nature before they were envisioned based on abstract knowledge (by Leo Szilard, in his bathtub).
It's not "blatantly false". To get from theory to practice you have to add to the theory various pieces of information about the practical issue. E.g. you might have a general theory of economics, but as a businessman you also have to consider the local details (which are not part of the general theory).
The general theory might tell you (in the best case scenario) what information you need to gather (e.g. Newtonian mechanics tells you that in order to solve specific problems you have to know the force and measure position and velocity at a given...
(Since there didn't seem to be one for this month, and I just ran across a nice quote.)
A monthly thread for posting any interesting rationality-related quotes you've seen recently on the Internet, or had stored in your quotesfile for ages.