alt Hacker NewsThe level of precision a subject can reach is peculiar to that subject, but it doesn't follow that nothing can be accurately predicated of it:
"It is characteristic of such knowledge [ethics] that it should be deficient in “exactness,” in precision of statement, and closeness of logical concatenation. We must not look for a mathematics of conduct. The subject-matter of Human Conduct is not governed by necessary and uniform laws. But this does not mean that it is subject to no laws."
"[T]he man of education will seek exactness so far in each subject as the nature of the thing admits, it being plainly much the same absurdity to put up with a mathematician who tries to persuade instead of proving, and to demand strict demonstrative reasoning of a Rhetorician."