168. _Metaphysical considerations_ also are brought up against my explanation of the moral cause of moral evil; but they will trouble me less since I have dismissed the objections derived from moral reasons, which were more impressive. These metaphysical considerations concern the nature of the _possible_ and of the _necessary_; they go against my fundamental assumption that God has chosen the best of all possible worlds. There are philosophers who have maintained that there is nothing possible except that which actually happens. These are those same people who thought or could have thought that all is necessary unconditionally. Some were of this [229] opinion because they admitted a brute and blind necessity in the cause of the existence of things: and it is these I have most reason for opposing. But there are others who are mistaken only because they misuse terms. They confuse moral necessity with metaphysical necessity: they imagine that since God cannot help acting for the best he is thus deprived of freedom, and things are endued with that necessity which philosophers and theologians endeavour to avoid. With these writers my dispute is only one of words, provided they admit in very deed that God chooses and does the best. But there are others who go further, they think that God could have done better. This is an opinion which must be rejected: for although it does not altogether deprive God of wisdom and goodness, as do the advocates of blind necessity, it sets bounds thereto, thus derogating from God's supreme perfection.