“In speaking of the work of machines and of natural forces we must, of course, in this comparison eliminate anything in which activity of intelligence comes into play. The latter is also capable of the hard and intense work of thinking, which tries a man just as muscular exertion does.” ThinkingMenTryingDoeHardPlayCoursesForceNaturalActivityCapableMachinesIntenseLatterComparisonExertion Book:Science and Culture: Popular and Philosophical Essays Source: Science and Culture: Popular and Philosophical Essays