The System of the World (The Baroque Cycle, #3)

by Neal Stephenson

Then he got a look on his face as if he were thinking. Daniel had learned, in his almost seventy years, not to expect much of people who got such looks, because thinking really was something one ought to do all the time.

“Human nature being what it is, I fear that this will only happen when the things that the Logic Mill is good at become important to a war. And that is a difficult thing to imagine.”

Just caught the theme carried through in Cryptonomicon.