Spinoza and Leibniz

Baruch Spinoza (1632-1677) and Gottfried Wilhelm von Leibniz (1646-1714) were the two most famous rationalists after Descartes.

Spinoza is famous for his monism, the belief that there is only one kind of thing, or only one thing.  All reality, he argued, is one thing, which we can call God or Nature (or God-or-Nature).

His argument in defense of this belief depends on the distinction between substances and properties.  Think of a ball.  It has various properties such as a certain weight, color, shape, etc.  The properties are properties, what has them is the substance.  We can't really say anything else about this substance, though, because all description is of properties, not substance itself.   Properties depend on substance (you can't have the weight of a thing without the thing), but substance, according to Spinoza, is independent. 

If it is truly independent it must not be limited by anything else, so it is unlimited, i.e. infinite.  And there can only be one infinite thing.  Therefore, there is only one substance (and hence only one kind of substance).

Minds and bodies, then, cannot be different kinds of thing.  They are the same thing perceived in different ways.

What we are is modifications (roughly: bits) of God-or-Nature.  We have no real free will of our own, but we can have a kind of freedom if we identify ourselves and our desires with God's will.  If we really want God's will to be done, then we will always get what we want (because God's will is always done).

Far from thinking that all things are one, Leibniz argued that there are lots and lots of distinct beings, which he calls monads.

The world can be divided almost infinitely and the basic building blocks must be absolutely simple, like mathematical points.  But since there is consciousness in reality, and consciousness cannot be made from unconscious things, these monads must all be conscious, perhaps to varying degrees.  The only difference between them is in their point of view.  But this 'point of view' is metaphorical only.  Each monad is completely independent of each other one, cut off, "windowless."  What the monads perceive is a sort of internal slide show programmed by God.  God has set these up to run at the same time in a pre-established harmony.  This is what explains the apparent interaction between different things in the world.  Nothing in the world really causes anything else to happen.  God is the sole cause of all things.

So why do bad things happen?  They must either not be bad, or else somehow they must be necessary.  If a better world were possible, God would  have made it.  This must be the best of all possible worlds.

Time and space have only a relative reality.  If time were real, when would it have begun?  And why would God have started it then rather than some other time?  There can be no reason, but nothing happens for no reason.   The same goes with space.  Why would God put space here rather than there?   Space cannot be an absolutely existing thing.  It can only be a relative thing, a matter of a certain kind of relation between physical objects (which are really clusters of monads perceived in a certain way).