In Book One of his Metaphysics Aristotle gives a brief history lesson on the evolution of knowledge.
“Hence when all such inventions were already established, the sciences which do not aim at giving pleasure or at the necessities of life were discovered, and first in the places where men first began to have leisure. This is why the mathematical arts were founded in Egypt; for there the priestly caste was allowed to be at leisure.” (Metaphysics, Book I, p. 1553).
Here he describes a departure from the condition of the “practical,” a condition which he uses to qualify the rest of his intellectual virtues. Even to art Aristotle prescribes a practical pursuit: to bring “into being” or to give pleasure (Nicomachean Ethics p. 1800). In this short passage Aristotle mentions a sort of pointless knowledge, with no utility beyond that of knowing for the sake of knowing, and certain conditions for pursuing this sort of knowledge—leisure. What he describes makes perfect sense; as human societies advance the goals of human society advance. Once human life was longer solely preoccupied with survival, with necessity, we were able to look up from the dirt, wonder why the sky is blue and then actually pursue that knowledge. This seems to imply that knowledge, what we even classify as knowledge, is determined by the flux of human goals and whims of the moment.
Although today we classify Set Theory as knowledge, there was surely a time in the past that such unnecessary information would not have been considered knowledge. Which seems crazy to me. Maybe in the future there will be a time where people pursue seriously, dedicate their whole lives to chasing, knowledge which we can’t even imagine or, even if we could, would consider useless. What we credit and think about has so much to do with leisure. Today all we seem to hear and believe is that “knowledge is priceless” and that “knowledge is the one thing which can never be taken away from you”. Yet it seems from this passage that knowledge, like anything else, carries a worth which fluctuates with the flow and supply of resources.