Up to now, the concept will has been subsumed under the concept force; but I am using it just the opposite way, and mean that every force in nature is to be understood as a function of will. And this is no mere squabble over words, or matter of no moment: on the contrary, it is of the greatest significance and importance. For at the back of the concept force there is finally our visual knowledge of the objective world, i.e., of some phenomenon, something seen. It is from this that the concept force derives. It is an abstraction from the field in which the laws of cause and effect prevail… whereas the concept will, on the contrary, is the one, among all possible concepts, that does not derive from the observation of phenomena, not from mere visual knowledge, but comes from inside, emerges from the immediate consciousness of each one of us, in which each is directly aware of his own individuality in terms of his own existence: not as a form, not even in terms of the subject-object relationship, but as that which he himself is; for here the knower and the known are the same.

— Arthur Schopenhauer