(Second of a three-part series…)

Spinoza’s naturalism lead him to atheism, but Leibniz came to Spinoza via his theism. That is, Leibniz found himself desperately trying to come up with an argument that showed that his own philosophy was not threatened by the spectre of Spinozism, but his philosophical commitments, especially those concerning the nature of God, meant his options were limited.

Leibniz, like Spinoza, has a characteristic commitment to the principle of sufficient reason (PSR), and once one has the PSR, as we’ve seen, it’s very easy to get to Spinozism given certain typical early modern philosophical assumptions.

But we can run it another way, which gets one to necessitarianism, another clear Spinozistic outcome.

Suppose there is an omniscient, omnipotent, omnibenevolent God, like the one Leibniz believes in. And God sets out to create a world, rifling through all the possibilities in God’s head. Which will God choose? God’s omnibenevolence will lead God to choose the best; God’s omniscience will ensure God knows which one is the best; and, God’s omnipotent ensures God is able to create the best of all possible worlds.

(It’s good to be da king.)

The PSR ensures that there is only one best possible world. Think of it like this. Suppose there were a tie between two equally good worlds; some philosophers and theologians thought there could be a tie. Then God’s decision to create would be arbitrary, because God would have picked that world without a good reason to do so. There would be no explanation as to why God created that particular world. The PSR rules that out.

The result is that there is exactly one world that God could create. This one. The best of all possible worlds. In fact, it looks as if God is determined by God’s nature to create the best of all possible worlds; how could a perfect being settle for anything less?

That is, it looks like, on Leibniz’s view, that God is determined to pick this world. This world, with its entire history and future, is the only way things could have been. And while Leibniz argues that God can still have meaningful freedom — he argues that if one’s actions are determined only by one’s nature, one can still count as free — there’s another problem.

Determinism is just the claim that past states determine future states. It doesn’t say anything about the possibility of various initial conditions. To get necessitarianism, one needs the further condition that there is only one possible starting point. Leibniz thinks that God necessarily exists, but the claim’s even stronger than that. God necessarily exists with the nature God has, because it is part of the nature of the ens perfectissimum, the most perfect being, to exist necessarily. As Leibniz wrote, “the reason for God is God.”

Necessary, necessary, necessary. God’s necessary nature thus entails that God necessarily chooses to create this necessitated world.

What’s the difference between this and Spinozism? Wishful thinking.*

Clearly Leibniz did not want to agree with Spinoza, and he tried a number of ways to save his view, among them distinguishing between certainty and necessity. It is certain (to use Leibniz’s own example), when God created the world, that Caesar would cross the Rubicon; but it was not necessary that Caesar cross the Rubicon, because doing otherwise wouldn’t result in a contradiction. But that seems like a distinction without a difference; Caesar could only do otherwise by not existing, but since this was the only world that God could create, it seems like Caesar has no choice but to exist and God has no choice but to create him.

And a God whose creation necessarily flows out of his existence sounds an awful lot like Spinoza’s God.

Leibniz muses:

…Therefore, the essence of all things is the same, and things differ only modally, just as a town seen from a high point differs from a town seen from a plain.

Hey, we’ve heard that before…

One wonders if, as he entered Spinoza’s house in late November 1676, he hoped to find a key difference between his own philosophy and that of the heretical Jew.**

*Well, if you think that Leibniz is unsuccessful, of course. I tend to think that he doesn’t manage to save his view from necessitarianism, but I could be talked out of it.

**Stewart takes a much stronger line: that Leibniz was a Spinozist, and didn’t want to admit it only because of the political risk. There’s a case to be made for that, but there’s also a case to be made that Leibniz was genuinely concerned about where his philosophy was leading him.