Objection 1. It would seem that counsel is not an inquiry. For Damascene says (De Fide Orth. ii, 22) that counsel is "an act of the appetite." But inquiry is not an act of the appetite. Therefore counsel is not an inquiry.
Objection 2. Further, inquiry is a discursive act of the intellect: for which reason it is not found in God, Whose knowledge is not discursive, as we have shown in the I, 14, 7. But counsel is ascribed to God: for it is written (Ephesians 1:11) that "He worketh all things according to the counsel of His will." Therefore counsel is not inquiry.
Objection 3. Further, inquiry is of doubtful matters. But counsel is given in matters that are certainly good; thus the Apostle says (1 Corinthians 7:25): "Now concerning virgins I have no commandment of the Lord: but I give counsel." Therefore counsel is not an inquiry.
On the contrary, Gregory of Nyssa [Nemesius, De Nat. Hom. xxxiv.] says: "Every counsel is an inquiry; but not every inquiry is a counsel."
I answer that, Choice, as stated above (13, 1, ad 2; 3), follows the judgment of the reason about what is to be done. Now there is much uncertainty in things that have to be done; because actions are concerned with contingent singulars, which by reason of their vicissitude, are uncertain. Now in things doubtful and uncertain the reason does not pronounce judgment, without previous inquiry: wherefore the reason must of necessity institute an inquiry before deciding on the objects of choice; and this inquiry is called counsel. Hence the Philosopher says (Ethic. iii, 2) that choice is the "desire of what has been already counselled."
Reply to Objection 1. When the acts of two powers are ordained to one another, in each of them there is something belonging to the other power: consequently each act can be denominated from either power. Now it is evident that the act of the reason giving direction as to the means, and the act of the will tending to these means according to the reason's direction, are ordained to one another. Consequently there is to be found something of the reason, viz. order, in that act of the will, which is choice: and in counsel, which is an act of reason, something of the will--both as matter (since counsel is of what man wills to do)--and as motive (because it is from willing the end, that man is moved to take counsel in regard to the means). And therefore, just as the Philosopher says (Ethic. vi, 2) that choice "is intellect influenced by appetite," thus pointing out that both concur in the act of choosing; so Damascene says (De Fide Orth. ii, 22) that counsel is "appetite based on inquiry," so as to show that counsel belongs, in a way, both to the will, on whose behalf and by whose impulsion the inquiry is made, and to the reason that executes the inquiry.
Reply to Objection 2. The things that we say of God must be understood without any of the defects which are to be found in us: thus in us science is of conclusions derived by reasoning from causes to effects: but science when said of God means sure knowledge of all effects in the First Cause, without any reasoning process. In like manner we ascribe counsel to God, as to the certainty of His knowledge or judgment, which certainty in us arises from the inquiry of counsel. But such inquiry has no place in God; wherefore in this respect it is not ascribed to God: in which sense Damascene says (De Fide Orth. ii, 22): "God takes not counsel: those only take counsel who lack knowledge."
Reply to Objection 3. It may happen that things which are most certainly good in the opinion of wise and spiritual men are not certainly good in the opinion of many, or at least of carnal-minded men. Consequently in such things counsel may be given.
Source: Summa Theologica (New Advent)