Objection 1. It would seem that the habit of knowledge acquired in this life does not remain in the soul separated from the body: for the Apostle says: "Knowledge shall be destroyed" (1 Corinthians 13:8).
Objection 2. Further, some in this world who are less good enjoy knowledge denied to others who are better. If, therefore, the habit of knowledge remained in the soul after death, it would follow that some who are less good would, even in the future life, excel some who are better; which seems unreasonable.
Objection 3. Further, separated souls will possess knowledge by influence of the Divine light. Supposing, therefore, that knowledge here acquired remained in the separated soul, it would follow that two forms of the same species would co-exist in the same subject which cannot be.
Objection 4. Further, the Philosopher says (Praedic. vi, 4,5), that "a habit is a quality hard to remove: yet sometimes knowledge is destroyed by sickness or the like." But in this life there is no change so thorough as death. Therefore it seems that the habit of knowledge is destroyed by death.
On the contrary, Jerome says (Ep. liii, ad Paulinum), "Let us learn on earth that kind of knowledge which will remain with us in heaven."
I answer that, Some say that the habit of knowledge resides not in the intellect itself, but in the sensitive powers, namely, the imaginative, cogitative, and memorative, and that the intelligible species are not kept in the passive intellect. If this were true, it would follow that when the body is destroyed by death, knowledge here acquired would also be entirely destroyed.
But, since knowledge resides in the intellect, which is "the abode of species," as the Philosopher says (De Anima iii, 4), the habit of knowledge here acquired must be partly in the aforesaid sensitive powers and partly in the intellect. This can be seen by considering the very actions from which knowledge arises. For "habits are like the actions whereby they are acquired" (Ethic. ii, 1). Now the actions of the intellect, by which knowledge is here acquired, are performed by the mind turning to the phantasms in the aforesaid sensitive powers. Hence through such acts the passive intellect acquires a certain facility in considering the species received: and the aforesaid sensitive powers acquire a certain aptitude in seconding the action of the intellect when it turns to them to consider the intelligible object. But as the intellectual act resides chiefly and formally in the intellect itself, whilst it resides materially and dispositively in the inferior powers, the same distinction is to be applied to habit.
Knowledge, therefore, acquired in the present life does not remain in the separated soul, as regards what belongs to the sensitive powers; but as regards what belongs to the intellect itself, it must remain; because, as the Philosopher says (De Long. et Brev. Vitae ii), a form may be corrupted in two ways; first, directly, when corrupted by its contrary, as heat, by cold; and secondly, indirectly, when its subject is corrupted. Now it is evident that human knowledge is not corrupted through corruption of the subject, for the intellect is an incorruptible faculty, as above stated (79, 2, ad 2). Neither can the intelligible species in the passive intellect be corrupted by their contrary; for there is no contrary to intelligible "intentions," above all as regards simple intelligence of "what a thing is." But contrariety may exist in the intellect as regards mental composition and division, or also reasoning; so far as what is false in statement or argument is contrary to truth. And thus knowledge may be corrupted by its contrary when a false argument seduces anyone from the knowledge of truth. For this reason the Philosopher in the above work mentions two ways in which knowledge is corrupted directly: namely, "forgetfulness" on the part of the memorative power, and "deception" on the part of a false argument. But these have no place in the separated soul. Therefore we must conclude that the habit of knowledge, so far as it is in the intellect, remains in the separated soul.
Reply to Objection 1. The Apostle is not speaking of knowledge as a habit, but as to the act of knowing; and hence he says, in proof of the assertion quoted, "Now, I know in part."
Reply to Objection 2. As a less good man may exceed a better man in bodily stature, so the same kind of man may have a habit of knowledge in the future life which a better man may not have. Such knowledge, however, cannot be compared with the other prerogatives enjoyed by the better man.
Reply to Objection 3. These two kinds of knowledge are not of the same species, so there is no impossibility.
Reply to Objection 4. This objection considers the corruption of knowledge on the part of the sensitive powers.
Source: Summa Theologica (New Advent)