Therefore we must recognise that it is one thing to be another's vicar, and that it is another to be his messenger or minister, just as it is one thing to be a doctor, and another to be an interpreter. For a vicar is one to whom is committed jurisdiction with law or with arbitrary power, and therefore within the bounds of the jurisdiction which is committed to him, he may act by law or by his arbitrary power without the knowledge of his lord. It is not so with a mere messenger, in so far as he is a messenger; but as the mallet acts only by the strength of the smith, so the messenger acts only by the authority of him that sent him. Although, then, God did this by His messenger Samuel, it does not follow that the Vicar of God may do the same. For there are many things which God has done and still does, and yet will do through angels, which the Vicar of God, the successor of Peter, might not do. Therefore we may see that they argue from the whole to a part, thus: Men can hear and see, therefore the eye can hear and see: which does not hold. Were the argument negative, it would be good: for instance, man cannot fly, therefore man's arm cannot fly. And, in the same way, God cannot, by his messenger, cause what is not to have been,[290] as Agathon says; therefore neither can his Vicar. [Footnote 290: As quoted by Aristotle, _Ethics_, vi. 3.--(W.)] VII.--Further, they use the offering of the wise men from the text of Matthew, saying that Christ accepted from them both frankincense and gold, to signify that He was lord and ruler both of things temporal and of things spiritual; and from this they infer that the Vicar of Christ is also lord and ruler both of things temporal and of things spiritual; and that consequently he has authority over both. To this I answer, that I acknowledge that Matthew's words and meaning are both as they say, but that the inference which they attempt to draw therefrom fails, because it fails in the terms of the argument. Their syllogism runs thus: God is the lord both of things temporal and of things spiritual, the holy Pontiff is the Vicar of God; therefore he is lord both of things temporal and of things spiritual. Both of these propositions are true, but the middle term in them is different, and _four_ terms are introduced, by which the form of the syllogism is not kept, as is plain from what is said of "the syllogism simply."[291] For "God" is the subject of the major premiss, and "the Vicar of God" is the predicate of the minor; and these are not the same. [Footnote 291: Arist. _Anal. Prior._, or rather, the _Summulæ Logicæ_, l. iv., of Petrus Hispanus.--(W.)]