Some one, however, may doubt whether every motion may be compared with every motion, or not. If, therefore, every motion may be compared, and that is equally swift, which, in an equal time, is moved through an equal space, there will be some periphery equal to, and also greater and less than a right line. Again, change in quality, and a certain lation, will be equal, when in an equal time the one is changed in quality, and the other has completed its motion. Hence, there will be a passive quality equal to length. This, however, is impossible. But when a thing is moved in an equal time through an equal space, it is then said to be equally swift. But passive quality is not equal to length; so that change in quality is neither equal to nor less than lation. All motion, therefore, cannot be compared. But in what manner will it happen in a circle, and a right line? For it would be absurd not to admit that this thing can be similarly moved in a circle, and that in a right line. But it is immediately necessary that it should be moved either more swiftly or more slowly; just as if the one should be in a declivity and the other in an acclivity. Farther still, it is of no consequence with reference to this reason, if it should be said it is necessary for it immediately to be moved swifter or slower: for the periphery will be greater and lesser than a right line; so that it will also be equal to a right line: for if in the time A the one should pass through the line B, and the other the line C, the line B will be greater than the line C; for thus it was said to be swifter. If, therefore, in a less time, it passes through an equal space, it will be swifter. So that there will be a certain part of the time A, in which the moveable B will pass through a part equal to the circle, and the moveable C in the whole time A will pass through the line C. If, however, the motions may be compared, that will happen which was just now observed, viz. that a right line is equal to a circle. But these two cannot be compared, and therefore the motions are not comparable. All such things however as are not homonymous may be compared. Thus, for instance, why is not a comparison to be made, which is the more sharp, a pen, or wine, or the lowest chord, nete? The answer is, because they are homonymous, they cannot be compared. But the nete may be compared with the paranete, or the chord next to the lowest, because the acute signifies the same thing in both. Whether, therefore, does the swift not signify the same thing here and there? But much less in change according to quality and lation. Or, in the first place indeed, shall we say, this is not true, that if they are not homonymous, they may be compared? For the much signifies the same thing in water and air; and yet these cannot be compared. But if this is not the case, yet the double signifies the same thing; for it is the ratio of two to one, and these do not admit of comparisons. Or, shall we say that in these there is the same ratio? For the much also is homonymous. But of some things the definitions also are homonymous: as if some one should say, that the much is so much, and something else besides; but the so much, and the equal, are homonymous. Unity indeed ia perhaps immediately homonymous; and if unity, also two. Since, why do some things admit of comparison, and others not? If there was one nature. Is it because they are in another first recipient? A horse, therefore, and a dog admit of comparison, with respect to which is the more white; for that in which whiteness is first inherent is the same, viz. superficies. After the same manner also, things may be compared according to magnitude. But water and voice cannot be compared, because they are in different subjects. Or is it not manifest that thus it may be possible to make all things to be one, and to say that each subsists in another? And the same thing will be equal, sweet, and white, but in something else. Farther still, not any thing what ever is a recipient, but there is one first recipient of one thing. Shall we say, therefore, it is not only requisite that things which may be compared should not be homonymous, but also that neither that which is compared, nor that in which it is inherent, should possess a difference? I say, for instance, colour possesses a difference, or division; there is not, therefore, any thing which may be compared according to this: as, for instance, whether it is more coloured, not according to a certain colour, but so far as it is colour. It may, however, be compared according to whiteness. Thus also in motion, that is said to be equally swift, which is moved in an equal time through so much equal. If, therefore, in this time, a part of a magnitude is changed in quality, and a part has been locally moved, will the change in quality be equal, and equally swift with the lation? But this would be absurd; and this because motion has species. Hence, if those things which are locally moved in an equal time, through an equal length, are equally swift, a right and a circular line will be equal. Whethcr, therefore, is this because lation is a genus, or because a line is a genus? For time is the same, being always indivisible in species. Or shall we say that they at the same time differ in species? For lation has species, if that hasspecies in which it is moved. Again, is local motion divided into species by reason of the instruments through which it is effected? As, for instance, if feet are the instruments, will it be walking; if wings, flying? Or is it not so, but lation is different from figures only? So that things which are moved through the same magnitude in an equal time, are equally swift. But it is the same magnitude, which has no specific difference; and in a similar manner the motion is the same, not being divided into species. So that this is to be considered, what the difference is of motion. And our present discourse indicates that genus is not one certain thing, but that it latently contains many things in itself. But of things homonymous, some are very much distant; others possess a certain similitude; and others are near, either in genus, or in analogy; on which account though they are homonymous, yet they do not appear to be so. When, therefore, is the species different? Is it when the same is in another, or when another is in another? And what is the definition? or by what shall we judge that the white and the sweet are the same, or different? Is it because a different species appears to be in another? or because, in short, it is not the same? With respect to change in quality, therefore, how is one equally swift with another? If, indeed, to acquire health is to be changed in quality, and it is possible that one person may acquire health swifter than another, it is also possible that certain persons may acquire health. So that change according to quality is equally swift; for it is changed according to quality in an equal time. But what is changed in quality? For the equal is not predicated here. But as is equality in quantity, so is similitude here. Let, however, the same thing which is changed in an equal time be equally swift. Whether, therefore, is it requisite to compare that in which the passion is, or the passion itself? Here indeed it may be assumed that there is the same health, or neither more nor less, but similarly inherent. But if the passion is different, as, for instance, that which becomes white is changed in quality, and also that which acquires health; in these there is nothing the same, nor equal, nor similar, so far as these make the species of change in quality; nor is there one change in quality only, as neither is there one lation. Hence it must be assumed how many species there are of change in quality, and how many species of lation. If, therefore, those things which are moved differ in species, viz. those things of which the motions are essential, and not according to accident;if this be the case, the motions also will be specifically different. But if they differ in genus, the motions will be generically, and if in number, numerically different. Is it, however, necessary to look to passive quality, whether it be the same, or similar, if changes in quality are equally swift? or to that which is changed in quality (as, for instance, if so much of this is whitened, but so much of that), or to both? And change in quality, indeed, is the same or different, by reason of passive quality, if passive quality is the same or different: but change in quality is equal or unequal. if passive quality is equal or unequal. In generation also, and corruption, the same thing must be considered, viz. how generation is equally swift, if in an equal time the same thing and an individual are generated, as, for instance, man, but not animal; and how it is swifter, if a different thing is generated in an equal, time: for we have not any two things in which there is diversity, as there is dissimilitude. And if essence is number, a greater or a lesser number is of the same species. But that which is common is anonymous, and also each; just as the passive quality which is more abundant, or exceeds, is said to be more; but the quantity is said to be greater.
