Objection 1. It would seem that the acts of the sensitive powers remain in the separated soul. For Augustine says (De Spiritu et Anima xv): "When the soul leaves the body it derives pleasure or sorrow through being affected with these" (namely the imagination, and the concupiscible and irascible faculties) "according to its merits." But the imagination, the concupiscible, and the irascible are sensitive powers. Therefore the separated soul will be affected as regards the sensitive powers, and consequently will be in some act by reason of them.
Objection 2. Further, Augustine says (Gen. ad lit. xii) that "the body feels not, but the soul through the body," and further on: "The soul feels certain things, not through the body but without the body." Now that which befits the soul without the body can be in the soul separated from the body. Therefore the soul will then be able to feel actually.
Objection 3. Further, to see images of bodies, as occurs in sleep, belongs to imaginary vision which is in the sensitive part. Now it happens that the separated soul sees images of bodies in the same way as when we sleep. Thus Augustine says (Gen. ad lit. xii): "For I see not why the soul has an image of its own body when, the body lying senseless, yet not quite dead, it sees some things which many have related after returning to life from this suspended animation and yet has it not when it has left the body through death having taken place." For it is unintelligible that the soul should have an image of its body, except in so far as it sees that image: wherefore he said before of those who lie senseless that "they have a certain image of their own body, by which they are able to be borne to corporeal places and by means of sensible images to take cognizance of such things as they see." Therefore the separated soul can exercise the acts of the sensitive powers.
Objection 4. Further, the memory is a power of the sensitive part, as proved in De Memor. et Remin. i. Now separated souls will actually remember the things they did in this world: wherefore it is said to the rich glutton (Luke 16:25): "Remember that thou didst receive good things in thy lifetime." Therefore the separated soul will exercise the act of a sensitive power.
Objection 5. Further, according to the Philosopher (De Anima iii, 9) the irascible and concupiscible are in the sensitive part. But joy and sorrow, love and hatred, fear and hope, and similar emotions which according to our faith we hold to be in separated souls, are in the irascible and concupiscible. Therefore separated souls will not be deprived of the acts of the sensitive powers.
On the contrary, That which is common to soul and body cannot remain in the separated soul. Now all the operations of the sensitive powers are common to the soul and body: and this is evident from the fact that no sensitive power exercises an act except through a bodily organ. Therefore the separated soul will be deprived of the acts of the sensitive powers.
Further, the Philosopher says (De Anima i, 4), that "when the body is corrupted, the soul neither remembers nor loves," and the same applies to all the acts of the sensitive powers. Therefore the separated soul does not exercise the act of any sensitive power.
I answer that, Some distinguish two kinds of acts in the sensitive powers: external acts which the soul exercises through the body. and these do not remain in the separated soul; and internal acts which the soul performs by itself; and these will be in the separated soul. This statement would seem to have originated from the opinion of Plato, who held that the soul is united to the body, as a perfect substance nowise dependant on the body, and merely as a mover is united to the thing moved. This is an evident consequence of transmigration which he held. And since according to him nothing is in motion except what is moved, and lest he should go on indefinitely, he said that the first mover moves itself, and he maintained that the soul is the cause of its own movement. Accordingly there would be a twofold movement of the soul, one by which it moves itself, and another whereby the body is moved by the soul: so that this act "to see" is first of all in the soul itself as moving itself, and secondly in the bodily organ in so far as the soul moves the body. This opinion is refuted by the Philosopher (De Anima i, 3) who proves that the soul does not move itself, and that it is nowise moved in respect of such operations as seeing, feeling, and the like, but that such operations are movements of the composite only. We must therefore conclude that the acts of the sensitive powers nowise remain in the separated soul, except perhaps as in their remote origin.
Reply to Objection 1. Some deny that this book is Augustine's: for it is ascribed to a Cistercian who compiled it from Augustine's works and added things of his own. Hence we are not to take what is written there, as having authority. If, however, its authority should be maintained, it must be said that the meaning is that the separated soul is affected with imagination and other like powers, not as though such affection were the act of the aforesaid powers, but in the sense that the soul will be affected in the future life for good or ill, according to the things which it committed in the body through the imagination and other like powers: so that the imagination and such like powers are not supposed to elicit that affection, but to have elicited in the body the merit of that affection.
Reply to Objection 2. The soul is said to feel through the body, not as though the act of feeling belonged to the soul by itself, but as belonging to the whole composite by reason of the soul, just as we say that heat heats. That which is added, namely that the soul feels some things without the body, such as fear and so forth, means that it feels such things without the outward movement of the body that takes place in the acts of the proper senses: since fear and like passions do not occur without any bodily movement.
It may also be replied that Augustine is speaking according to the opinion of the Platonists who maintained this as stated above.
Reply to Objection 3. Augustine speaks there as nearly throughout that book, as one inquiring and not deciding. For it is clear that there is no comparison between the soul of a sleeper and the separated soul: since the soul of the sleeper uses the organ of imagination wherein corporeal images are impressed; which cannot be said of the separated soul. Or we may reply that images of things are in the soul, both as to the sensitive and imaginative power and as to the intellective power, with greater or lesser abstraction from matter and material conditions. Wherefore Augustine's comparison holds in this respect that just as the images of corporeal things are in the soul of the dreamer or of one who is carried out of his mind, imaginatively, so are they in the separated soul intellectively: but not that they are in the separated soul imaginatively.
Reply to Objection 4. As stated in the first book (Sent. i, D, 3, qu. 4), memory has a twofold signification. Sometimes it means a power of the sensitive part, in so far as its gaze extends over past time; and in this way the act of the memory will not be in the separated soul. Wherefore the Philosopher says (De Anima i, 4) that "when this," the body to wit, "is corrupted, the soul remembers not." In another way memory is used to designate that part of the imagination which pertains to the intellective faculty, in so far namely as it abstracts from all differences of time, since it regards not only the past but also the present, and the future as Augustine says (De Trin. xiv, 11). Taking memory in this sense the separated soul will remember [Cf. I, 77, 8; I, 89, 6].
Reply to Objection 5. Love, joy, sorrow, and the like, have a twofold signification. Sometimes they denote passions of the sensitive appetite, and thus they will not be in the separated soul, because in this way they are not exercised without a definite movement of the heart. In another way they denote acts of the will which is in the intellective part: and in this way they will be in the separated soul, even as delight will be there without bodily movement, even as it is in God, namely in so far as it is a simple movement of the will. In this sense the Philosopher says (Ethic. vii, 14) that "God's joy is one simple delight."
Source: Summa Theologica (New Advent)