As for those who agree with Empedocles that the elements of body are more than one, so that they are not transformed into one another--one may well wonder in what sense it is open to them to maintain that the elements are comparable. Yet Empedocles says For these are all not only equal...
If it is meant that they are comparable in their amount, all the comparables must possess an identical something whereby they are measured. If, e.g. one pint of Water yields ten of Air, both are measured by the same unit; and therefore both were from the first an identical something. On the other hand, suppose (ii) they are not comparable in their amount in the sense that so-much of the one yields so much of the other, but comparable in power of action (a pint of Water, e.g. having a power of cooling equal to that of ten pints of Air); even so, they are comparable in their amount, though not qua amount but qua Iso-much power. There is also (iii) a third possibility. Instead of comparing their powers by the measure of their amount, they might be compared as terms in a correspondence: e.g. as x is hot, so correspondingly y is white. But correspondence, though it means equality in the quantum, means similarity in a quale. Thus it is manifestly absurd that the simple bodies, though they are not transformable, are comparable not merely as corresponding, but by a measure of their powers; i.e. that so-much Fire is comparable with many times-that-amount of Air, as being equally or similarly hot. For the same thing, if it be greater in amount, will, since it belongs to the same kind, have its ratio correspondingly increased.
A further objection to the theory of Empedocles is that it makes even growth impossible, unless it be increase by addition. For his Fire increases by Fire: And Earth increases its own frame and Ether increases Ether. These, however, are cases of addition: but it is not by addition that growing things are believed to increase. And it is far more difficult for him to account for the coming-to-be which occurs in nature. For the things which come-to-be by natural process all exhibit, in their coming-to-be, a uniformity either absolute or highly regular: while any exceptions any results which are in accordance neither with the invariable nor with the general rule are products of chance and luck. Then what is the cause determining that man comes-to-be from man, that wheat (instead of an olive) comes-to-be from wheat, either invariably or generally? Are we to say Bone comes-to-be if the elements be put together in such-and such a manner? For, according to his own estatements, nothing comes-to-be from their fortuitous consilience, but only from their consilience in a certain proportion. What, then, is the cause of this proportional consilience? Presumably not Fire or Earth. But neither is it Love and Strife: for the former is a cause of association only, and the latter only of dissociation. No: the cause in question is the essential nature of each thing-not merely to quote his words) a mingling and a divorce of what has been mingled. And chance, not proportion, is the name given to these occurrences: for things can be mingled fortuitously.
The cause, therefore, of the coming-to-be of the things which owe their existence to nature is that they are in such-and-such a determinate condition: and it is this which constitutes, the nature of each thing--a nature about which he says nothing. What he says, therefore, is no explanation of nature. Moreover, it is this which is both the excellence of each thing and its good: whereas he assigns the whole credit to the mingling. (And yet the elements at all events are dissociated not by Strife, but by Love: since the elements are by nature prior to the Deity, and they too are Deities.)
Again, his account of motion is vague. For it is not an adequate explanation to say that Love and Strife set things moving, unless the very nature of Love is a movement of this kind and the very nature of Strife a movement of that kind. He ought, then, either to have defined or to have postulated these characteristic movements, or to have demonstrated them-whether strictly or laxly or in some other fashion. Moreover, since (a) the simple bodies appear to move naturally as well as by compulsion, i.e. in a manner contrary to nature (fire, e.g. appears to move upwards without compulsion, though it appears to move by compulsion downwards); and since (b) what is natural is contrary to that which is due to compulsion, and movement by compulsion actually occurs; it follows that natural movement can also occur in fact. Is this, then, the movement that Love sets going? No: for, on the contrary, the natural movement moves Earth downwards and resembles dissociation, and Strife rather than Love is its cause-so that in general, too, Love rather than Strife would seem to be contrary to nature. And unless Love or Strife is actually setting them in motion, the simple bodies themselves have absolutely no movement or rest. But this is paradoxical: and what is more, they do in fact obviously move. For though Strife dissociated, it was not by Strife that the Ether was borne upwards. On the contrary, sometimes he attributes its movement to something like chance (For thus, as it ran, it happened to meet them then, though often otherwise), while at other times he says it is the nature of Fire to be borne upwards, but the Ether (to quote his words) sank down upon the Earth with long roots. With such statements, too, he combines the assertion that the Order of the World is the same now, in the reign of Strife, as it was formerly in the reign of Love. What, then, is the first mover of the elements? What causes their motion? Presumably not Love and Strife: on the contrary, these are causes of a particular motion, if at least we assume that first mover to be an originative source.
An additional paradox is that the soul should consist of the elements, or that it should be one of them. How are the souls alterations to take Place? How, e.g. is the change from being musical to being unmusical, or how is memory or forgetting, to occur? For clearly, if the soul be Fire, only such modifications will happen to it as characterize Fire qua Fire: while if it be compounded out of the elements, only the corporeal modifications will occur in it. But the changes we have mentioned are none of them corporeal.