05 April 2006

The Inaudible and Noiseless Foot of Time

I mentioned yesterday that there are some passages in Aristotle which seem difficult to reconcile with the thesis that time is in any way mind dependent. In both passages, Aristotle argues that time has no boundary, either a beginning or an end. In both passages, he argues by pointing to the connection between time and change.

These arguments would clearly be unsound, if some other condition besides change were necessary (the existence of a mind) in order for time to exist. Moreover, in both passages Aristotle's mention of time seems gratuituous, in the sense that an appeal to change would seem to be sufficient. But then why would he appeal additionally to something that he regarded as introducing extra assumptions and conditions?

The first passage is from Metaphysics Lambda (ch. 6, 1071b3-11)

Since there were three kinds of substance, two of them physical and one unmovable, regarding the latter we must assert that it is necessary that there should be an eternal unmovable substance. For substances are the first of existing things, and if they are all destructible, all things are destructible. But it is impossible that movement should either have come into being or cease to be (for it must always have existed), or that time should. For there could not be a before and an after if time did not exist (a)ll' a)du&naton ki/nhsin h2 gene/sqai h2 fqarh~nai-a)ei\ ga_r h}n-ou)de\ xro&non. ou) ga_r oi[o&n te to_ pro&teron kai\ u3steron ei]nai mh_ o1ntoj xro&nou). Movement also is continuous, then, in the sense in which time is; for time is either the same thing as movement or an attribute of movement.
This argument denies a beginning of time, arguing from this to the eventual conclusion that an eternal thinking substance exists. But that would be a circular argument, if time presupposed a thinking being.

The second is from the Physics discussion of time itself:
Will time then fail? Surely not, if motion always exists. (a}r' ou}n u(polei/yei; h)\ ou)/, ei)/per ai)ei\ e)/sti ki/nhsij;) Is time then always different or does the same time recur? Clearly time is, in the same way as motion is (dh~lon o3ti w(j a2n h( ki/nhsij, ou3tw kai\ o( xro&noj). For if one and the same motion sometimes recurs, it will be one and the same time, and if not, not (Physics 4.13, 222a29-32).
As regards this passage, there would be an obvious rejoinder to Aristotle's conclusion if time required the existence of a mind that can count: Why should the repetition of the same motion imply the repetition of the same time, if that motion were counted differently in each occurrence (just as we can use the same fingers to count to 20 or 30, as well as to 10)?

Also, it's not clear, even, that the passage in Physics that most suggests the mind-dependence of time isn't dialectical. And the way in which it raises the difficulty is strange. Why develop this in terms of impossibility ("if it is impossible that a counter exists, then it is impossible that anything countable exist")? The very manner in which Aristotle phrases this makes one suspect he regards it as a false argument. (And do we want to say that, for Aristotle, numbers too are mind-dependent?):
Whether if soul did not exist time would exist or not, is a question that may fairly be asked; for if there cannot be some one to count there cannot be anything that can be counted (a)duna&tou ga_r o1ntoj ei]nai tou~ a)riqmh&sontoj a)du&naton kai\ a)riqmhto&n ti ei]nai), so that evidently there cannot be number; for number is either what has been, or what can be, counted. But if nothing but soul, or in soul reason, is qualified to count, there would not be time unless there were soul, but only that of which time is an attribute, that is, if movement can exist without soul, and before and after are attributes of movement, and time is these qua numerable (Physics 4.14, 223a21-28)
Apart from these passages, there is also the consideration that Aristotle lists 'time' as a category (that is, a sort of thing indicated by a sort of predicate). By parity, we should no more expect that time is mind-dependent than what is indicated by any other category.

Let me clarify my concern here. I'm wondering how Coope deals with these passages, since they seem on their face at odds with a main the thesis of the book. And I wish that the reviewer in NDPR had addressed these concerns!