From the diversity of forms follows a difference of activities, and further a diversity of agents and patients, properties and accidents.
Evidently then it is not without reason that divine providence distributes to creatures different accidents and actions and impressions and allocations. Hence it is said: The Lord by wisdom hath founded the earth, hath established the heavens in prudence. By his wisdom the depths have broken out, and the clouds grow thick with dew (Prov. iii, 19, 20).
As it is necessary for one wishing to build a house to look out for timber, but his looking out for pitch-pine (ligna abietina) depends on his mere will, not on his plan of building a house; so it is necessary for God to love His own goodness, but it does not thence necessarily follow that He should wish to have that goodness represented by creatures, since the divine goodness is perfect without that. Hence the bringing of creatures into being depends on the mere will of God, although it is done in consideration of the divine goodness. Supposing however that God wishes to communicate His goodness by way of similitude as far as possible, it logically follows thence that there should be creatures of different sorts: but it does not follow of necessity that creatures should be of this or that grade of perfection, or exist in this or that number. But supposing that it is in the divine will to wish this number in creation, and this grade of perfection in each creature, it thence follows logically that creation be in such and such form, and such and such matter; and so of further consequences. Manifestly then providence disposes of things according to a certain plan, and yet this plan presupposes the divine will.
What has been said shuts out two errors, the error of those who believe that all things follow mere will without reason, which is the error of sundry Doctors of the Mohammedan law, as Rabbi Moses says; according to whose teaching, the only difference between fire warming and fire freezing is God's so willing the former alternative;* and again the error is shut out of those who say that the order of causes springs from divine providence by way of necessity.
There are certain words of Holy Scripture which appear to put down all things to the mere will of God. Their meaning is not to take away all rational character from the dispensations of Providence, but to show that the will of God is the first principle of all things. Such texts are: All things, whatsoever he hath willed, the Lord hath done (Ps. cxxxiv, 6:) Who can say to him, Why doth thou so? (Job ix, 12:) Who resisteth his will? (Rom. ix, 19.) And Augustine ( De Trin. III:) "Nothing but the will of God is the prime cause of health and sickness, of rewards and punishments, of graces and recompenses."
Thus in answer to the question, Why? asked of any natural effect, we can render a reason from some proximate cause, yet so that we reduce all things to the prime cause. Thus if it is asked why wood gets hot in presence of fire, it is answered [etc., etc., in terms of Aristotelian physics], and so on till we come to the will of God [who willed to create matter and energy, such as we know them, from the beginning]. Hence whoever answers the question, why the wood got hot, Because God has willed it so, answers appropriately, if he intends to carry back the question to the prime cause; but inappropriately, if he intends to exclude all other causes.*
3.96 : That God does not hear all Prayers
3.99 : How God can work beyond the Order laid down for Creatures, and produce Effects without Proximate Causes