1. Finally, he asks whether there is only one “age” of the angels, or several. He gives four objections.
2. First, that in 3 Esdras (which he notes is apocryphal) several ages are spoken of. Second, that there are different genera of aeviternal things, and thus there ought to be different temporal measures of each. Since the age is the measure of an aeviternal thing with respect to temporality, there should be multiple ages. Third, that not all aeviternal things are simultaneous, so since they differ as to their duration and change, they should be measured by different measures, and thus exist in different ages. Fourth, he observes that the unity of time is a consequence of the unity of the prime mover’s act in causing everything that exists in time. Whatever things are not dependent on each other or on some common cause don’t seem to have a common measure of duration, but are accounted for separately. But spiritual creatures are independent of each other, so they should belong to separate ages.
3. The fact that he cites an apocryphal work as an authority while noting its lack of canonicity says much about St. Thomas’s understanding of authority. Today we are generally inclined to think of authority in terms of strict divisions of ligation. “What am I bound to accept?” asks the modern student of the tradition. Thomas evidently is not very interested in this question, although he considers it briefly in his discussion of the virtue of faith at the beginning of the Secunda Secundae. Since 3 and 4 Esdras are outside the canon, we are inclined to exlcude them from the tradition as well, but even if these books are not divinely inspired, the faithful have found in them signs of inspiration sufficient to bring them into the circle of ecclesiastical books. There is something to be learned from them. Though not included in the canon, the apocryphal works have authority by their closeness to the canon, and by the consistent use the faithful have made of them for instruction and edification.
4. For his Sed Contra, he gives a quick argument: there is only one time, but “age” is simpler as such than time, so it follows that there should only be one age.
5. The Corpus of this article is very complex. St. Thomas attempts to solve the question of the number of the “ages” by solving the more general question: “What unites any sort of temporal measure?” Since it is easier to asnwer this question by thinking about the unity of time, he begins there, and considers several views on the reason for the unity of time.
6. One view, which he rejects, is that time is one because time is a quantity, and quantity is the same regardless of what is measured by it. He explains that the inference is false: the identity of quantity or number (e.g. “five”) is the same because it is abstracted from the things measured. Time is not an abstract measure, but a measure of the quantity of change in things, i.e. it is in the things measured by it. He goes on to point out that abstract quantity isn’t a reason for the unity of what is measured by it. If I have a certain quantity of iron, for example, it doesn’t matter for the quantity as such whether the iron has been drawn into wire, or melted and shaped as ingots or bars. The unity of the thing measured is left indeterminate by abstract quantity. Quantitative unity is always based on some other prior unity (unity of form, of place, of relation, etc.) and therefore cannot account for the oneness of time.
7. Then he considers two other views, which he also rejects: first that the unity of time is based on the oneness of eternity, which is the principle of all duration. Second, that the unity of time is based on the continuity of prime matter, which is the underlying subject of every material thing that exists in time. He rejects them both because they work by appealing to a distant causal principle, and obviously things that can be reduced to the same cause (in the order of material causation, as with prime matter, or in the order of efficient causation, as with eternity) may nonetheless be distinct. So while the claims made in each of these views are true, they are not sufficient to account for the unity of time.
8. Next he supplies his own solution to the problem. He draws on Aristotle’s account of unity in Book X of the Metaphysics. Aristotle says that the basis for some common measure is something simple and indivisible, which is known first. Thomas takes as the principle for the measure of time the primum motum, the first moved, which Garrigou-Lagrange takes to be the sun. However, since we are more interested in the truth of Thomas’s views than in their application to the cosmology of his day, we should look into the cosmological function of the primum motum as regards time. It seems that this can be looked at in two ways: in the order of knowledge, Aristotle says that the unite of measure is what is known first. The motion of the sun is the first motion which is constant and simple, so that we can use it to measure the duration of other things. The truth of this, historically speaking, is wittnessed in certain vestigial features of our society (clocks and calendars, especially), which are referred to the movement of the sun as their principle. But setting aside the movement of the sun, we can identify the features of the primum motum, whatever it is, that guarantee the unity of time. The primum motum has these features: its motion is constant, unaltering, and fast, so that whatever else changes can be measured by it, and is somehow present to it. Whatever that is is the real basis for the constancy of the measure of time, and any true measure we use to mark of particular durations must have its value relative to that primum motum, whatever it may be.
9. Now, St. Thomas takes this idea and extends it to spiritual creatures. He says that just as the unity of the measure of time is a result of the unity of the primum motum, if there is only one aevum, it is measured by what most permanent among aeviternal things. He entertains the opinion, attributed to Origin in his Peri Archon, that there is equality among the angels, so that none of them are the “highest” or closest to God’s eternity. But against this he cites Pseudo-Denys, who says that the angels exist in strict hierarchy. It follows, depending on which view is more correct, that there will either be many “ages”, since many different principles could be referred to as the principle of the measurement of all aeviternal beings as to their duration and change, or there will be only one, if there is one highest principle of aeviternity, since the modifications of each will be referrable somehow to that one highest being.
10. There are many moving pieces in the Corpus of this article, so I will provide a linear recap: Time is the quantity of motion with respect to before and after. Time is a measure of changing things. So when we ask why there is one time, we're asking how everything that moves can have its motion measured by some unit of motion as to its beginning, end, and duration. Now, the quantity of time can't just be reduced to the quantity of change, because the same change can happen faster or slower. Nor can the quantity of time be reduced to the common cause of all temporal things (eternity), since the eternal is so remote from temporal things is itself without change, that the quantity of change cannot be measured by it. Whatever accounts for the unity of time, then, must be something constantly moving, but by an unaltering motion that is (more or less) ever-present to mobile things, so that every other motion, at whatever time, can be referred back to the regular motion of this thing. Thomas calls that the "primum motum", the first moved. This makes sense given Aristotle's account of measurement in Metaphysics X, where he says that the principle of measurement should be what is simplest and constant. So when Thomas asks whether the angels can all be measured by one time, the question isn't really whether their transformations occur simultaneously or successively, but whether in their transformations there is some first thing which is simple and constant in its quasi-eternity, so that every other transformation can be referred back to it. So in the end the question becomes one about the hierarchy of the angels, since simplicity and permanence in spiritual things are marks of perfection and therefore closeness to God. So he cites two opinions: the opinion of Origin, who attributes equality to the angels in the Peri Archon, and Dionysius, who famously distinguishes the angelic hierarchies. Aquinas favors Denys's account, and therefore concludes that there is only one "aevum" to which all the temporalities of the angels can be referred. He reserves further discussion of the hierarchies to later on in the Prima Pars. The question will return both in the treatise on the Angels (QQ.50ff.) and the treatise on the Divine Government (QQ.103ff).
11. The replies to the objections are quite brief: First, he explains that the passage in 3 Esdras uses aevum as a synonym for saeculum, i.e. a period of the duration of a specific thing. So in saying that God has the power of ages (potestas aevorum), the text is speaking of his power over every measure and duration of time. Second, that whatever genera of aeviternal beings there are all agree in being “intransmutable”, i.e. incapable of corruption into a different substance, and are all subject to the same order and measure as regards their duration. Third, he says that all things are measured by the first thing: temporal things by the primum motum, and aeviternal things by whatever is first in their genus. Fourth, he says that the reason one thing is the measure of the others in its genus is not necessarily that it is the cause of the rest, but that it is the simplest.
OUTLINE OF ARTICLE
- 3 Esdras speaks of “ages”.
- Different genera of aeviternals ought to have different aevi.
- Not all aeviternal things begin simultaaneously, so there must be separate aevi.
- Commensurate things have a common cause, but aeviternal things are independent of each other.
- First we consider the reason for the unity of time.
- Different opinions exist: on account of the unity of number, or the unity of eternity, or the unity of prime matter. None of these suffice, because the unity they give is either secondary or secundum quid.
- The unity of time is the unity of that motion which is simplest and constant, by which all things can be measured.
- Thus the unity of the aevum depends on whether there is something simplest and most constant by which the motion of the aeviternals can be measured.
- There is, but the argument for this is deferred to Q.47.
- Here “aevum” is used to mean “saeculum”.
- The different genera are united in their intransmutability.
- Simultaneity is not required: the common measure of all is the first in the genus.
- The common measure need not be the common cause, but only the simplest in the genus.