The objections which can be made against this manner of viewing things do not much differ from those which we have solved in our second article on space; and therefore we do not think it necessary to make a new answer to them. The reader himself will be able to see what the objections are, and how they can be solved, by simply substituting the words “eternity,” “duration,” etc., for the words “immensity,” “space,” etc., in the article referred to.
Yet a special objection can be made against the preceding doctrine about the duration of movement, independently of those which regard relations in space. It may be presented under this form. “The foundation of the relation between _before_ and _after_ is nothing else than movement itself. It is therefore unnecessary and unphilosophical to trace the duration of movement to the virtuality of God’s eternity as its extrinsic foundation.” The antecedent of this argument may be proved thus: “That thing is the foundation of the relation which gives to its terms their relative being--that is, in our case, their opposite formalities, _before_ and _after_. But movement alone gives to the _when_ these opposite formalities. Therefore movement alone is the foundation of successive duration.”
We answer that the antecedent of the first argument is absolutely false. As to the syllogism which comes next, we concede the major, but we deny the minor. For it is plain that movement cannot give to the absolute _when_ the relative formalities _before_ and _after_, except by flowing through absolute duration, without which it is impossible for the movement to have its successive duration. And surely, if the movement has no duration but that which it borrows from the absolute duration through which it extends, the foundation of its duration from _before_ to _after_ can be nothing else than the same absolute duration through which the movement acquires its _before_ and _after_. Now, this absolute duration is the virtuality of God’s eternity, as we have proved. It is therefore both philosophical and necessary to trace the duration of movement to the virtuality of God’s eternity, as its extrinsic foundation. That movement is also necessary to constitute the relation between _before_ and _after_, we fully admit; for there cannot be _before_ and _after_ without movement. But it does not follow from this that movement is the _foundation_ of the relation; it merely follows that movement is a _condition_ necessary to give to the absolute _when_ two distinct actualities, according to which it may be compared with itself on the ground of standing duration. For, as every relation demands two opposite terms, the same absolute _when_ must acquire two opposite formalities, that it may be related to itself.