Objection 1. It would seem that, while in this state, Paul's soul was wholly separated from his body. For the Apostle says (2 Corinthians 5:6-7): "While we are in the body we are absent from the Lord. For we walk by faith, and not by sight" ['Per speciem,' i.e. by an intelligible species]. Now, while in that state, Paul was not absent from the Lord, for he saw Him by a species, as stated above (Article 3). Therefore he was not in the body.
Objection 2. Further, a power of the soul cannot be uplifted above the soul's essence wherein it is rooted. Now in this rapture the intellect, which is a power of the soul, was withdrawn from its bodily surroundings through being uplifted to divine contemplation. Much more therefore was the essence of the soul separated from the body.
Objection 3. Further, the forces of the vegetative soul are more material than those of the sensitive soul. Now in order for him to be rapt to the vision of God, it was necessary for him to be withdrawn from the forces of the sensitive soul, as stated above (Article 4). Much more, therefore, was it necessary for him to be withdrawn from the forces of the vegetative soul. Now when these forces cease to operate, the soul is no longer in any way united to the body. Therefore it would seem that in Paul's rapture it was necessary for the soul to be wholly separated from the body.
On the contrary, Augustine says (Ep. CXLVII, 13, ad Paulin.; de videndo Deum): "It is not incredible that this sublime revelation" (namely, that they should see God in His essence) "was vouchsafed certain saints, without their departing this life so completely as to leave nothing but a corpse for burial." Therefore it was not necessary for Paul's soul, when in rapture, to be wholly separated from his body.
I answer that, As stated above (1, Objection 1), in the rapture of which we are speaking now, man is uplifted by God's power, "from that which is according to nature to that which is above nature." Wherefore two things have to be considered: first, what pertains to man according to nature; secondly, what has to be done by God in man above his nature. Now, since the soul is united to the body as its natural form, it belongs to the soul to have a natural disposition to understand by turning to phantasms; and this is not withdrawn by the divine power from the soul in rapture, since its state undergoes no change, as stated above (3, ad 2,3). Yet, this state remaining, actual conversion to phantasms and sensible objects is withdrawn from the soul, lest it be hindered from being uplifted to that which transcends all phantasms, as stated above (Article 4). Therefore it was not necessary that his soul in rapture should be so separated from the body as to cease to be united thereto as its form; and yet it was necessary for his intellect to be withdrawn from phantasms and the perception of sensible objects.
Reply to Objection 1. In this rapture Paul was absent from the Lord as regards his state, since he was still in the state of a wayfarer, but not as regards the act by which he saw God by a species, as stated above (3, ad 2,3).
Reply to Objection 2. A faculty of the soul is not uplifted by the natural power above the mode becoming the essence of the soul; but it can be uplifted by the divine power to something higher, even as a body by the violence of a stronger power is lifted up above the place befitting it according to its specific nature.
Reply to Objection 3. The forces of the vegetative soul do not operate through the soul being intent thereon, as do the sensitive forces, but by way of nature. Hence in the case of rapture there is no need for withdrawal from them, as from the sensitive powers, whose operations would lessen the intentness of the soul on intellective knowledge.
Source: Summa Theologica (New Advent)