All right, I'll give it a try:
Medieval Europe in 1220 AD is extremely hierarchical, and this is reinforced by religion: all authority ultimately flows from God, to his chosen ruler the King, to the nobles, and down to the peasants. Likewise the father has been placed by God as head of his family. And of course the Catholic Church is just as hierarchical. In this mindset, the precise nature of the laws or orders that are given are irrelevant to the fact that disobeying them is in fact challenging God's order on Earth. (That is the philosophy, of course, I'm not saying all medieval men were actual despots who lorded it over their family at every turn).
House Tytalus, then, is a reaction against that concept of absolute authority (and a rather extreme one, but then extreme concepts breed extreme reactions). For a Tytalus, there is no natural order (God-ordained or otherwise) that puts any man in authority over another. That is in fact the whole point of the apprenticeship: to guide the apprentice to the conclusion that arbitrary rules have no intrinsic value whatsoever, and should not be obeyed because of any intrinsic authority of the figure who set them (but because they are advantageous to the one obeying, or at least because pf the threat of force if he disobeys).
Yep, it does sound a lot like teenage rebellion on steroids. But as they are rebelling against far worse bounds that most teenagers this days, they tend to go even farther in the rebellion.
And it's not exactly an isolated phenomenon in the Medieval world, it's only that it takes a House of magi to make it stick: witness the numerous peasant rebellions, the heresies (some of which also rejected the concept of authority); or, in a completely different (and peaceful) register, the monastic rule of St. Benedict, which holds that all the monks are equals in the abbey, including the abbot. Of course, apart from the Benedictine Order (which is ultimately still suborned in authority to the Pope), all the others were violently suppressed, and would continue to be for centuries. It does not mean that people were not rebelling, just that they were not successful.
Now, as for the specific philosophy of physis versus nomos, I'm certainly not educated enough in the classics to tell you where it comes from and whether there were other examples in the medieval world an in religion. I'm almost tempted to say that as far as Christianity goes, the Tytalus would share many beliefs with the Protestant Reformation; the Calvinists, perhaps. Not that they are around yet, but a devout Tytalus might advance similar beliefs (while another might go straight to existential nihilism seven centuries early). But besides the fact I'm quite likely talking of things I know not enough about, that's beyond the original question of Tytalus and 1220 AD... except that socially and religiously, the 13th century is not that different from the 16th century which did bring the Protestant Reformation).
Here you are then, the Tytalus are not selfish thugs and bullies, they are visionaries centuries before their time. Or at least, they are progressive selfish thugs and bullies.