 We say that that which is capable of some particular faculty or possession has suffered privation [sterêsis] when the faculty or possession in question is in no way present in that in which, and at the time in which, it should be naturally present. We do not call that toothless which has not teeth, or that blind which has not sight, but rather that which has not teeth or sight at the time when by nature it should. (Categories 12a28–33)