Philosophical Instructions

Lesson Forty-Three: What is Time?

Discussion about the Reality of Time

Strange positions have also been reported regarding the reality of time, to which Ibn Sīnā has referred in thePhysics of hisShifā . However, it seems that the solution of the problem of time was easier for Muslim philosophers than the problem of space, for they are almost entirely in agreement that time is a kind of continuous quantity characterized by instability and which by means of motion becomes an accident of bodies. In this way, the position of time in the Aristotelian table of categories becomes perfectly clear. Ṣadr al-Muta’allihīn has also presented this explanation in numerous places, but in the final analysis of the problem of motion, he states a new view which is especially important.

No matter how clear the explanation of time given by the philosophers is, if one is precise about it one will encounter ambiguous and questionable points which require deep thought. Perhaps it is these which attracted the fine and insightful attention of Ṣadr al-Muta’allihīn, and led him to present a new theory of time.

In order to explain these points something must be mentioned about the principles of the philosophers related to this question, even though this is not really the place to discuss and research them.

Philosophers normally introduce motion as an ‘accident,’ but do not explain this any further. Only some of them have regarded it as of the category of ‘that which acts’ or ‘that which is acted upon.’ Shaykh al-Ishrāq considered it to be an independent category alongside substance, quantity, quality and relation. In this way, he limited the number of categories to five, and he considered the others as types of relation. Perhaps one may infer from the words of other philosophers that they have not considered motion itself to be among the categories.

Another principle is that motion is confined to four categories (quantity, quality, position, and place), and they consider transferal to be a motion in the category of place. They imagined that motion in the other categories, including substance, was impossible. Therefore, motion, considered to be an intermediary between bodies and time, was inevitably taken to be motion in one of the four categories of accidents.

On the other hand, all of them accepted the theory of the ninefold celestial spheres as axiomatic, and they related the appearance of time to the circular rotation of the highest firmament. This point is also presented in some places by Ṣadr al-Muta’allihīn.

Regarding these principles and points, questions may be raised about the famous definitions of time, among the most important of which are the following:

1. There is no doubt that time is extended and divisible, and hence is considered to be a kind of quantity or to possess a kind of quantity, but why should it be considered as a quantity of motion?

The simple answer which is given to this question is that time is flowing and not fixed, such that not even two moments of it coexist, and necessarily one part of it must pass before the following part may come into existence.

This sort of quantity can only be related to something which is inherently flowing and not fixed, and that would be nothing other than motion.

As was indicated, this answer depends on the fact that gradualness, flux and instability are particular to motion, a motion which is presumed to be specified to the four categories of accidents, and for this reason they deny the possibility that time could be a quantity for corporeal substance. But is this doctrine correct? If it is supposed that there were no accidental motion in the world, would there then be no room for the concept of motion?

2. Motion is an intermediary between bodies and time, but what kind of intermediary is it? Is it a fixed intermediary (wāsiṭah dar thubūt ),1 from which it could be concluded that bodies themselves really possess time by means of motion, or is it an accidental intermediary (wāsiṭah dar ‘urūḍ ), such that bodies themselves never really possess time? In other words, is the attribution of corporeal substance to time an accidental characterization (ittiṣāf bil-‘araḍ )?

Perhaps the answer which must be given on the basis of the principles [of the mentioned philosophers] to this question is to accept the second alternative. But is it correct to accept that bodies themselves do not possess time, regardless of their continuous and gradual changes? If we suppose that all changes are instantaneous but successive, will there be no precedence and posteriority among them?

Let us assume that they consider motion to be a fixed intermediary and that the true attribution of possessing time by bodies is considered to be posterior to the occurrence of motion. This assumption implies that bodies essentially have the capacity for the attribution of this quantity which results from motion, although prior to the occurrence of motion bodies do not have this attribution actually. Before it takes the form of a ball or cube, wax has such a capability, for it possesses extension and volume. However, the ancient philosophers did not see any way for the influence of flux and motion in the essences of bodies, so how could they accept the attribution to such existents of an attribute which is flux and instability itself? This is just like the case in which we want to relate line, surface and volume, even if by means of a cause, to an abstract existent which lacks extension, in a way that these qualities will really be attributed to it!

3. Another question is what kind of relation is that between motion and time? Is motion the cause for the appearance of time, as so many of the philosophers seem to hold, or is it merely that which serves as the subject of the accidental attribution of time? In any case, in what category should motion itself be included? How is its attribution to time to be determined?

It was previously indicated that some of the philosophers, such as Shaykh al-Ishrāq, considered motion to be an independent category of accidents. Others considered motion to be two-sided: they considered the side related to its agent [i.e., the mover] to be in the category of that which acts, and they considered the side related to its object, the moved, to be in the category of that which is acted upon. Other philosophers have given no clear explanation. In any case, the answer to this part of the question requires greater precision. However, the application of cause and effect to motion

and time may be considered a kind of development of the terminology of causality, similar to what was indicated in Lesson Thirty-Seven.

4. Another question which can be raised is that if the standard for relating time to motion is its essential instability, this is found in all motions; so why do the philosophers relate time to the rotation of the Sphere of Atlas [the highest of the celestial spheres of traditional cosmology]? And if there were no Sphere of Atlas or it had no motion, would the other phenomena of the cosmos not posses temporal priority or posteriority? And basically, how can an accident which