They can't apply for a patent in those categories, so they have no way of preventing others from reading their text (or using a program to process the text, and compute statistical properties), and using the ideas in other contexts (without re-expressing the same text).

If someone reads a philosophical essay, has a heureka moment from it, applies the principle to their work, and makes bank (commercial profit), they never have to pay a percentage to the author of the essay.