| The Underground Peripatetic | |||||||||||||||||
| Marc Berquist on Motion |
SUMMARY of different views about motion and how it is to be defined. (The following seem to be the principal views; other views would seem to be intermediate. Not many take an explicit position; usually a position is implied in discussion of some question about motion.) (1) There is no such thing as motion or change; there only appears to be motion. For if there were really motion or change, something would both be and not be at once, the most absurd of all falsehoods. (Parmenides and Zeno are the best known (and most formidable) of those who hold this position. (2) There really is motion, but it is not a distinct actuality. It is only a series of momentary states. This, for example, change of place is no more than the occupation of different places, one after the other, without delaying at any one of them. [This is analogous to the view that a line is not made up of points, which amounts to saying that a line is not a different kind of thing from a point but is merely many points arranged in some order.] Bertrand Russell is a clear exponent of this position, though it is by no means unique to him. It is the typical view of mathematicians and mathematical physicists. (3) There really is motion, and it is a discinct actuality, but it is indefinable -- not because it is absurd or unintelligible, but because there is nothing more basic in being or in understanding by which it might be defined. Descartes is perhaps the chief exponent of this position: ... don't they seem to bring forth magic words, which have a power hidden and beyond the grasp of the human mind, who say that motion, a thing most known to everyone, is in the act of a being in potency, insofar as it is in potency? For who understands these words? And who is ignorant of what motion is? And who would not admit that they have looked for a knot on a bulrush? It should be said, therefore, that things are never to be explained by definitions of this sort, lest we take composite things in place of simple ones, but that they should only be intuited attentively by each one, apart from all other things, and by the light of his own mind. (Descartes Rules for the Direction of the Mind, XII.) This position is somewhat like that of Meno, in the Platonic dialogue (71b-e); Meno recognizes that there are questions and problems about virtue -- e.g. whether it can be taught -- but not that there is a problem in knowing what it is. In other words, for him, there is no problem of definition. However, those who hold this position sometimes seem to advance a sort of circular definition of motion, when they attempt to state more clearly what it is: ... let us consider what ought to be understood by motion according to the truth of the thing; we may say, in order to attribute a determinate nature to it, that it is the transference of one opart of the matter or one body from the vicinity of those bodies that are in immediate contact with it, and which we regard as in repose, into the vicinity of others. (Descartes Principles of Philosophy, Part II, xxv.) This account, if it is advanced as a definition rather than a description, is circular in several ways: it defines a universal ( | ||||||||||||||||
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I shall begin with some of the Presocratics, without whom Aristotle's doctrine will not be fully intelligible on the subject which will concern us. menides, as you might know, composed a poem On Nature, which begins with a description of his passage from darkness to light, from illusion to the presence of the Goddess of Truth. She speaks, as it were, the doctrines we find in the poem, as distilled through his own mind. After the introduction, the first t of the poem concerns The Way Of Truth. Here, in his own words, is some of that truth: There remains, then, but one word by which to express the (true) road: IS. And on this road there are many signs that What Is has no beginning and never will be destroyed: it is whole, still, and without end. It neither was nor will be, it simply is... How could you go about investigating its birth? How and whence could it have grown? I shall not allow you to say or think of it as coming from not-being, for it is impossible to say or think that not-being is. Necessarily, therefore, either it simply IS or it simply IS NOT. Strong conviction will not let us think that anything springs from Being except itself. ...Thus our decision must be made in these terms: IS or IS NOT...How could WHAT IS be something of the future? How could it come-to-be? For if it were coming-to-be, or if it were going to be in the future, in either case there would be time when it was not. Thus coming-to-be is quenched, and destruction is unthinkable.... Moreover it is immovable, held so by mighty bonds. And it is without beginning and end, because both creation and destruction have been driven away by true belief. Remaining always the same and in the same place by itself, it stays fixed where it is...Natural law forbids that Being should be other than perfectly complete. Thinking and the object of thought are the same. For you will not find thought at from being, nor either of them at from utterance. Indeed, there is not anything at all at from being...Accordingly, all the usual notions that mortals accept and rely on as if true - coming-to-be and perishing, being and not-being, change of place and variegated shades of color - these are nothing more than names. I have quoted these passages because they contain an important doctrine, one which takes on an unexpected significance when we consider modern science. Empedocles, though admitting a plurality of elements, and their congregation and segregation, yet agrees with menides in one central teaching: They are fools, he says, with no ability to reach out with their thoughts who suppose that what formerly Was Not could come into being, or that What Is could perish and be utterly annihilated. From what Is Not it is impossible for anything to come- to-be, and it is neither possible nor conceivable that What Is should utterly perish. For it will always be no matter how it is disposed of. And I tell you something more. there is no birth in mortal things, and no end in ruinous death. There is only mingling and interchange of ts, and it is this that we call | Ron MacArthur on Change | ||||||||||||||||
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| Duane Berquist on Substance | Just a little theological footnote to the category of substance. If you ask whether God is in the genus of substance, the answer is | ||||||||||||||||
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