Book III, Chapter XII
But from reason they thus argue: they take the principle laid down in the tenth book of "Philosophia Prima,"1 saying that all things which belong to one genus are to be brought under one head, which is the standard and measure of all that come under that genus. But all men belong to one genus: therefore they are to be brought under one head, as the standard and measure of them all. But the Supreme Pontiff and the Emperor are men; therefore if the preceding reasoning be true, they must be brought under one head. And since the Pope cannot come under any other man, the result is that the Emperor, together with all other men, must be brought under the Pope, as the measure and rule of all; and then, what those who argue thus desire follows.
To overset this argument, I answer that they are right when they say that all the individuals of one genus ought to be brought under one head, as their measure; and that they are again right when they say that all men belong to one genus, and that they are also right when they argue from these truths that all men should be brought under one head, taken from the genus man, as their measure and type. But when they obtain the further conclusion concerning the Pope and the Emperor, they fall into a fallacy touching accidental attributes.
That this thing may be understood, it must be clearly known that to be a man is one thing, and to be a pope or an emperor is another; just as to be a man is different from being a father or a ruler. A man is that which exists by its essential form, which gives it its genus and species, and by which it comes under the category of substance. But a father is that which exists by an accidental form, that is, one which stands in a certain relation which gives it a certain genus and species, and through which it comes under the category of relation. If this were not so, all things would come under the category of substance, seeing that no accidental form can exist by itself, without the support of an existing substance; and this is not so. Seeing, therefore, that the Pope and the Emperor are what they are by virtue of certain relations: for they owe their existence to the Papacy and the Empire, which are both relations, one coming within the sphere of fatherhood, and the other within that of rule; it manifestly follows that both the Pope and the Emperor, in so far as they are Pope and Emperor, must come under the category of relation; and therefore that they must be brought under some head of that genus.
I say then that there is one standard under which they are to be brought, as men; and another under which they come, as Pope and Emperor. For in so far as they are men, they have to be brought under the best man, whoever he be, who is the measure and the ideal of all mankind; under him, that is, who is most one in his kind,2 as may be gathered from the last book to Nicomachus.3 When, however, two things are relative, it is evident that they must either be reciprocally brought under each other, if they are alternately superior, or if by the nature of their relation they belong to connected species; or else they must be brought under some third thing, as their common unity. But the first of these suppositions is impossible: for then both would be predicable of both, which cannot be. We cannot say that the Emperor is the Pope, or the Pope the Emperor. Nor again can it be said that they are connected in species, for the idea of the Pope is quite other than the idea of the Emperor, in so far as they are Pope and Emperor. Therefore they must be reduced to some single thing above them.
Now it must be understood that the relative is to the relative as the relation to the relation. If, therefore, the Papacy and the Empire, seeing that they are relations of paramount superiority, have to be carried back to some higher point of superiority from which they, with the features which make them different,4 branch off, the Pope and Emperor, being relative to one another, must be brought back to some one unity in which the higher point of superiority, without this characteristic difference, is found. And this will be either God, to whom all things unite in looking up, or something below God, which is higher in the scale of superiority, while differing from the simple and absolute superiority of God. Thus it is evident that the Pope and the Emperor, in so far as they are men, have to be brought under some one head; while, in so far as they are Pope and Emperor, they have to be brought under another head, and so far is clear, as regards the argument from reason.
Footnotes
Chapter 41 of 45