Via Matt Birchler, TIL about Muppet Theory. It is a humorously reductive conception of humankind as falling into one of two types, a Chaos Muppet or an Order Muppet:

The same thing is true of Muppet Theory, a little-known, poorly understood philosophy that holds that every living human can be classified according to one simple metric: Every one of us is either a Chaos Muppet or an Order Muppet.

Chaos Muppets are out-of-control, emotional, volatile. They tend toward the blue and fuzzy. They make their way through life in a swirling maelstrom of food crumbs, small flaming objects, and the letter C. Cookie Monster, Ernie, Grover, Gonzo, Dr. Bunsen Honeydew and—paradigmatically—Animal, are all Chaos Muppets. Zelda Fitzgerald was a Chaos Muppet. So, I must tell you, is Justice Stephen Breyer.

Order Muppets—and I’m thinking about Bert, Scooter, Sam the Eagle, Kermit the Frog, and the blue guy who is perennially harassed by Grover at restaurants (the Order Muppet Everyman)—tend to be neurotic, highly regimented, averse to surprises and may sport monstrously large eyebrows. They sometimes resent the responsibility of the world weighing on their felt shoulders, but they secretly revel in the knowledge that they keep the show running.

Not that he invented it exactly, but German philosopher Friedrich Nietzsche wrote at length about a similar dichotomy: the Apollinian and the Dyonisian:

What does Nietzsche mean by DI and AP? The latter is derived from the concept of Apollo, the Greek god of light, who is often said to rule over the realm of the self-conscious, and is thus strongly related to the idea of individuation, through which he provides the world around us with a sensible structure. In contrast we have Dionysus, god of festivals (among other things), ‘centred in extravagant sexual licentiousness’ where ‘the most savage natural instincts were unleashed’ (Nietzsche, 1993, p.147)

The world, to Nietsche, was shaped by the tension between the order and individualism of the Apollinian–whose artistic explication finds itself in sculpture–and the Diononysian–which finds expression in music. Especially in art, the overly controlled rationality of the Apollinian impoverished expression, although the unbidden Dionysian–like too much id and not enough superego, in Freud’s conception–lacked adequate discipline.

The Dionysian and the Apollonian in Nietzsche: The Birth of Tragedy