 We come by the idea of power though considering the possibility of changes in our ideas made by experiences and our own choices. Yet, to consider this possibility—of some things making a change in others—we must already have a concept of power, rationalists would say. Empiricists, on the other hand, would point out, again, that what we actually need is for our minds to be able to recognize this, by having the correct abilities and faculties. Just as we don’t need to have a concept telling us how it is that we have binocular vision, being able to recognize change would be cashed out by us having the requisite faculty enabling us to do so.