Angels can move locally, but in a different manner from bodies which are contained and measured by place, which, in consequence of their continuity, have a continuous motion. The angels being present is by contact of power, as containing place, not as measured by it. Their local motion consists simply of different contacts with different places, successive, and not simultaneous, because an angel cannot be in several places at once. Nor is it necessary that such contacts should be continuous; for the angel may either leave a material place successively, and thus the motion would be continuous; or leave the whole place at once and apply itself at once to the whole of another place; in which case the motion would not be continuous.
If the angel's motion be continuous it cannot move from one extreme to the other without passing through the middle, as Aristotle proves; but if the movement be not continuous the angel may pass without going through the middle. This is impossible to a body which is extended and contained in place; but the substance of the angels is not subject to place as being contained by it, nay, it is superior as containing it; hence they have power to apply themselves to place as they will, either with or without medium.
The movement of the angels is, however, necessarily in time, for where there are several movements there must be time, time being nothing else than before and after. If their motion be continuous, it is therefore in time continuously, and not so if the motion be not continuous; for the motion of an angel may be according to either mode. This time, however, is not the same as that which measures the movement of the heavens, and constitutes the standard by which all corporeal things, mutable through the change of the heavens, are measured: for the motion of the angels does not depend upon that of the heavens.
- text taken from Compendium of the Summa Theologica of Saint Thomas Aquinas, by Bishop Berardus Bongiovanni