Again, we think Pleasure must be in some way an ingredient in Happiness, and of all Workings in accordance with Excellence that in the way of Science is confessedly most pleasant: at least the pursuit of Science is thought to contain Pleasures admirable for purity and permanence; and it is reasonable to suppose that the employment is more pleasant to those who have mastered, than to those who are yet seeking for, it.
– Aristotle, Nicomachean Ethics