Dante Alighieri is a very philosophical poet, but he's something of an odd bird with regard to his philosophy. This comes out very strikingly in the fourth book of the Convivio. One of his major concerns in this book is to address a claim made by Frederick the Great, that gentilezza or nobility is ancestral wealth and fine manners. Dante is firmly against this bit of philosophical legislation on the part of an Emperor; and in arguing against the right of the Emperor to address the issue, he makes some very strong, very unusual claims.
The Emperor, Dante says, exists due to the human need for society, which we establish in order to live a happy life (because we can't provide everything necessary for such a life ourselves). The complete fulfillment of this need can only exist when all human societies are united into a single principality, with a Monarch capable of keeping all the lesser kings in line. Thus, the perfection of the human species requires a "universal and indisputable office of command," the office of the Emperor. By experience, says Dante, we have found that the Emperor should be Roman, because the Latin race is seen to have a natural talent for the exercise of rule and acquisition of power, and because in history God in his divine providence clearly gave sway to the Romans. Rome had a special birth, a special development, a special end. The world needs a Roman Emperor, someone who can be "rider of the human will," who can have authority over all practical, voluntary activities.
That's a strong claim, and an unusual one, but that's not the claim I was talking about. The claim I was talking about was this: in contrast to the practical realm, the philosophical realm is not governed by the Emperor but by Aristotle, to whom we are all required to render "faith and obedience." Yes, obedience. For Dante, Aristotle is to philosophy what the Emperor is to politics; he exercises a universal and indisputable office of command as the teacher and leader of human reason. Here is what Dante says, in the Lansing translation (IV, 6):
That Aristotle is the most worthy of faith and obedience may be proved as follows. Among workmen and craftsmen of various arts and activities which are ordained to a single final activity or art, the craftsman or workman pursuing such an end must above all be obeyed and trusted by everyone as being he alone who considers the final end of all the other ends. Hence the knight should be trusted by the sword-maker, the bridle-maker, the saddle-maker, the shield-maker, and all trades that are established for the purpose of achieving the goals of chivalry. Since all human activities require a final end, namely the end of human life to which man is directed insofar as he is human, the master or the craftsman who studies this and reveals it to us should be obeyed and trusted above all others. That man is Aristotle: he therefore is the most worthy of faith and obedience.
It's hard to get more plain than that. Other philosophers deserve our respect inasmuch as they approximate to Aristotle, and Aristotle, like a Pope in spiritual matters or an Emperor in political matters, because of "his singular and almost divine genius," is to hold full sway. He is il sommo Filosofo, the supreme philosopher, the Philosopher himself. He is "invested with complete power". This power is not opposed to the Emperor's power, but requires it and is required by it; without the Emperor's authority, Aristotle's authority is weak, and without Aristotle's authority, the Emperor's authority is dangerous. To have good government, each must keep to its domain, and each must exercise unconditional authority over that domain. It's clear enough that this means mostly the primacy of Aristotle in ethical matters -- it is chiefly for this reason that the Emperor needs to respect the domain of Aristotle. And it is worth pointing out that the actual result of this is the freedom of philosophy from every external imposition: neither the Emperor nor the Pope have any direct say in philosophical matters. But we still have Aristotle as the philosopher-king of philosophy itself.
That is a very strong, very unusual claim. Needless to say, even Aristotelians would usually balk at the idea that Aristotle not only deserves respect but complete trust and obedience as the Supreme and Sovereign Philosopher. But Dante is not just any Aristotelian; he is in a sense the most vehemently Aristotelian Aristotelian of them all, the one who holds that philosophy was given to Aristotle by God as his own personal empire. Etienne Gilson notes in Dante and Philosophy that this odd sort of move is actually very characteristic of Dante's thought. In every realm of human endeavor, there is need for a proper ammaestramento, instruction by a proper authority. So Dante divides human life into distinct and air-tight domains, each with its proper authority, each such authority subject only to God in that domain. Such thinking pervades the Divine Comedy. Gilson points out that throughout the Comedy Dante repeatedly condemns those who try to usurp authority (as he would see it) -- thus Pope Boniface is in hell -- but repeatedly forgives those who, whatever their errors, tried to preserve distinct domains. Thus he's very forgiving of the Fraticelli (and thus Joachim) even though he thinks they went too far, because they insisted that the Church should keep to spiritual things and leave matters of property to the Empire. And he's also very forgiving of Siger, even though he probably thinks he went too far, because Siger tried to preserve the distinct authority of Aristotle. So Siger and Joachim are lauded in heaven by their more saintly earthly opponents, Aquinas and Bonaventure. As Gilson sums it up:
And where, it will be said, are those who wish to exercise [authority] where they do not have it? They are in Hell. And it may indeed be said that they alone have put themselves there by their violation of the holy law of divine Justice which is not only the supreme creator of the constitutive orders of nature and supernature, but also the inexorable protector of the authorities which it has wisely placed at their head. There is no greater crime than to betray the divine order, and it is betraying it to refuse to follow Aristotle in the matter of philosophy, because philosophy is the daughter of God and it was God Himself Who desired that it should be taught to us by Aristotle. But it is no less a crime for a Franciscan to betray St. Francis, for a Dominican to betray St. Dominic, for a subject to betray the Emperor, for a Christian to betray the Gospel, and the worst crime of all, the one which in this world gives rise to disorders, abuses, wars and miseries without number, is to betray all forms of authority at once through a desire to install one of them, which is competent in its sphere, in the place of those which are equally so in theirs, for each form of authority is master in its own house and even the humblest of all is directly responsible to God alone.
[Etienne Gilson, Dante and Philosophy. David Moore, tr. Harper & Row (New York: 1963), p. 156]
That's what you can call an extreme commitment to subsidiarity. And, as I said, it's a very strong, very unusual sort of philosophical viewpoint.