We’re deep inside contingency and necessity this week. And one good joke. Regular followers of this series will recall St Thomas was not immune of the temptation to pun. Chapter 83 may be skimmed.
 …Likewise neither does it follow that there is changeableness. For if there is no potentiality in God’s will, the reason why, in His effects, He does not of necessity give preference to the one alternative, is not because He is considered to be indifferent to either alternative, so as to be at first potentially willing either, and afterwards willing actually (whereas He is always actually willing whatsoever He wills, with regard not only to Himself but also His effects); but it is because the thing willed is not necessarily related to the divine goodness, which is the proper object of the divine will; in the same way in which we say that an enunciation is not necessary but possible where the predicate is not necessarily related to the subject.
Hence when we say: God wills this effect, this statement is clearly not necessary but possible, in the same way as a thing is said to be possible, not in reference to a potentiality, but because it is neither necessary nor impossible for it to be, as the Philosopher teaches (6 Metaph.). Thus the statement that a triangle has two equal sides is possible, yet not in reference to a potentiality, since in mathematics there is neither potentiality nor movement. Therefore the exclusion of the aforesaid necessity does not remove the unchangeableness of the divine will…
Notes As always, recall that God is outside time. God creates time. This is why the discussion of unchangeableness. We must relate to God, who is changeless and outside time, from being inside of it. Time is change. We cannot therefore ascribe to God’s mind powers that only belong to us. These few chapters thus answer the seeming objections that “God changes Him mind” or “God is or was surprised” or “God is open to the future” and such like.
 …For it has been proved that the divine will is unchangeable. Now that which is once in an unchangeable thing cannot afterwards not be therein: since we say that a thing is changed when its condition is different now to what it was before. Therefore, if God’s will is unchangeable, supposing that He will something, it is necessary by supposition that He will it.
 Again. Everything eternal is necessary. Now that God will some particular effect to exist is eternal: for His willing, like His being, is measured by eternity. Therefore it is necessary. Not however if we consider it absolutely: because God’s will has not a necessary relation to this particular thing willed. Therefore it is necessary by supposition.
 Further. Whatsoever God could do, He can do, for His power is not diminished, as neither is His essence. But He cannot now not will what He is supposed to have willed, since His will is unchangeable. Therefore He never could not will whatever He has willed. Therefore it is necessary by supposition that He willed, as also that He will, whatever He willed: neither however is necessary absolutely, but possible in the aforesaid manner.
Notes Say this one three times fast! Okay, so this is true, but unsatisfying in some sense, and will be, too, because it doesn’t tell us why God does what He does nor how. But then we aren’t God and our finite minds cannot comprehend such things anyway. Think about Job!
 Moreover. Whosoever wills a thing, necessarily wills those things which are necessarily requisite to that thing, unless there be a defect on his part, either through ignorance, or because he is led astray from the right choice of means to the end in view, by some passion. But these things cannot be said of God. Wherefore if God, in willing Himself, wills something other than Himself, it is necessary for Him to will all that is necessarily required for what is willed by Him: even so is it necessary for God to will that there be a rational soul, supposing that He wills a man to be.
Notes And so He did will.
 HENCE it is clear that God’s will cannot be of things that are impossible in themselves.
 For the like are those which imply a contradiction in themselves: for instance that a man be an ass, which implies that rational is irrational. Now that which is incompatible with a thing excludes some of those things which are required for that thing: for instance, to be an ass excludes man’s reason. If, then, He wills necessarily the things that are required for those He is supposed to will, it is impossible that He will those that are incompatible with them. Hence it is impossible for Him to will things that are simply impossible.
Notes Ha ha ha! Anyway, here’s the answer to the unstoppable cannon ball meeting the immovable flag pole or any other man-made contradiction such as God can will 2 + 2 = 5. God cannot will the impossible. And this isn’t a limitation, but a perfection. This, really, is the reason the universe is predictable and comprehensible. The next arguments amplify this. Incidentally, how many readers made it to the joke?
 Again. As was proved above, God, by willing His own being, which is His own goodness, wills all things as bearing a likeness to Him. Now in so far as a thing is incompatible with the notion of being as such, it cannot retain a likeness to the first, that is, the divine being, which is the source of being. Wherefore God cannot will that which is incompatible with the notion of being as such. Now just as irrationality is incompatible with the notion of man as such, so is it incompatible with the notion of being as such, that anything be at the same time a being and a non-being. Hence God cannot will affirmation and negation to be true at the same time. Yet this is implied in everything which is in itself impossible, that it is incompatible with itself, in as much as it implies a contradiction. Therefore God’s will cannot be of things impossible in themselves…
Notes Hence mathematics! And don’t think about going all Godel here. That man’s theorems are about proofs, and proofs are the collection of necessarily true premises that demonstrate the truth of a proposition. Things can be true without us proving them. What Godel showed was that men cannot prove everything without assuming; indeed, this was always plain. Axioms, initial premises, are assumptions. And these axioms, given by a certain form of induction (I use this word in classical and not modern sense), must be in a sense, gifts of God.