They had time-traveling email!

There's this... thread... line of thinking?... idea that keeps popping up?... that runs through a series of philosophers.

Start with the Greeks, before Socrates. Everyone wanted the complexity of the world around them to be reduced to something simple. Either everything really was simple (and the complexity was an illusion), or everything came out of a simple First Cause.

Supposedly Greek philosophy started with a guy named Thales, who managed to accurately predict a solar eclipse using math rather than magic. Everyone gasped and was amazed and got in on the fun. And then Parmenides came along.

Parmenides said that either something exists, or nothing exists; no in between. But if existence is, y'know, existence, then change is impossible. After all, once things start changing, then the things in existence will eventually no longer exist--but nonexistence is impossible, if existence exists. (Or something like that.) Everyone else either said, "Holy crap, he's right!" or "No way in Hades!" and frantically tried to explain how things could exist while changing (or change could exist without things). Some of 'em decided (along with Parmenides) that the world around us is an illusion; others (like Heraclitus) decided that change is itself the only thing that exists. Meanwhile, the proto-science nerds were busy trying to figure out what the primal element was that gave rise to everything else.

For instant, Empedocles, my favorite early philosopher, invented the dark and light sides of the Force. He developed a complex system of change/existence, in which four elements--earth, air, fire, water--and two forces--Love and Strife--keep the cosmos going in a constantly changing cycle, eerily similar to early Big Bang/Big Crunch theories.

This kept going until Plato jumped in. He took all these simple-to-complex ideas and codified them into one theory: God Did It. God is the simple; from him comes the complex. In a rather complex system of its own. Everything we see around us--people, cats and dogs, trees, tables, etc.--all resemble other members of their species/class of objects because all of them are simply echoes of the Idea of Man, the Idea of Cat, the Idea of Dog, the Idea of Tree, the Idea of Table. (You get the idea.) These ideas--or Forms--exist in the mind of God, and only there are they perfect. All this ridiculous complexity, change, death, disease--everything unpleasant takes place because this world is an imperfect reflection of the perfect existence in the Intellect of God.

[If this sounds awfully Christian, it's because Aquinas jumped on the Neo-Platonic bandwagon and introduced Catholicism to Plato. First they called him a heretic; then when they finally figured out what he was saying, they called him the Doctor of the Church.]

Then comes Plotinus. He liked Plato so much that in the process of passing on, illuminating, and expanding Plato's ideas, he turned the system into something all his own. God, the First Cause, he called the One. Nothing simpler than One-ness, right? He thought that through a series of "emanations," everything came into being. This wasn't a creation event that happened through time, though; it's more like a reality ladder. You've got the One, which organizes itself into Intellect and Spirit. Intellect is the realm of ideas, similar to the Forms of Plato. Intellect contemplates the One, and creates Forms. Spirit is what the Forms do. Spirit contemplates Intellect, and produces the world of the senses. Our job as sensory beings is to turn back through Spirit and Intellect and eventually return to the One.

[Plotinus was used by, and fought against, both Gnostic and Orthodox Christians. He had a helluva time walking a fine line between them, while owing allegiance to neither.]

This philosophy seems to disappear (or else I'm just not reading widely enough) until Maester Eckhart. He was a German mystic theologian who was tried for heresy, but died before the verdict came down. He also believed in a source similar to Plotinus' One, from which all creation proceeded (but this time in a Christian package). All people shared in the divine soul, since everyone was descended from this single source. By turning inward and contemplating one's own soul, a person could meet God. No priests necessary.

[Gee, I wonder why he was tried as a heretic...]

Then enter Benedict Spinoza. He's like Plotinus' little brother. He's a philosophical descendent in the Greek tradition, all the way down from Parmenides. Spinoza, of course, says that the only thing in existence is God--which in accordance with Parmenides is unchanging. He then proceeds to rewrite Plotinus, using attributes and modes instead of Intellect and Spirit. Only one thing exists--because if more than one thing existed, both things would be limited by each other, and would in effect cancel each other out. (Or something like that.) This one thing has attributes of existence, infinity, mind, motion, and extension (it's the eternal adjective club). These attributes in turn embody themselves in modes, which is basically Idea condensed into what we would call reality (a cluster of deterministic nouns).

[Oddly enough, Spinoza was kicked out of his synagogue for talking about this stuff.]

A few more centuries down the line, we run headfirst into Fichte, and then Schelling. Fichte was the reincarnation of Spinoza, in the same way that Kant was the reincarnation of Parmenides. However, Fichte turned Spinoza's determinism on its head by saying that, since you have to start with a first principle, then human freedom (the existential kind) makes a dandy one. Not surprisingly, he ran into all sorts of trouble. No matter how many iterations of his system he published (last count was two million three hundred thousand and one), no one could understand what he was saying. Then they accused him of atheism (not quite a capital offense any more, but you'd lose your job, your paycheck, and your reputation over it), then he almost single-handedly invented German National Socialism by characterizing the German people as the best embodiment of the divine (thereby committing the worst theological error a pantheist can), and everyone conveniently forgot about him.

...Except for his student, Schelling. Schelling was to Fichte what Jung was to Freud. Everything starts out flowers and chocolate, then they start fighting over money, and pretty soon they're sleeping in separate bedrooms and not speaking to each other.

In another desperate attempt to remove Spinoza's uncomfortable determinism from the budding idealism, Schelling wound up reinventing Empedocles. Instead of Love and Strife, though, he made all existence a push-pull between the unconscious and the conscious, the objective and subjective, deterministic nature and existentially free mind. This muddy dualism hid an underlying monism that said that determinism and free will were, yet again, just two sides of the same coin. (So much for trying to get rid of Spinoza.)

All of which is to say, there really are no new ideas. Every new genius philosophy is the reincarnation of somebody else a thousand years or so ago. Schelling was Empedocles. Kant was Parmenides. Avatar was Dances With Wolves.

But for the real mind-bending stuff, read Marcus Aurelius' Meditations right next to the Tao te Ching. Somehow these two guys, inhabiting different eras, cultures, languages, and sides of the planet, wrote down almost the exact same ideas about religion, government, and human nature.