Anthony Quinton on Spinoza & Leibniz

Once Descartes set the agenda and got modern philosophy started, the greatest thinkers of Europe divided into roughly two camps: the empiricists, like Locke, Berkeley and Hume, who argued that substantive knowledge about the world comes exclusively from experience; and the rationalists, who argued that reason alone, independent from experience, could produce substantive knowledge about existence.

Two of the most famous and profound rationalists were Spinoza and Leibniz. As rationalists, they believed that reason alone, independent of experience, can deduce the deepest of metaphysical truths. Science, on their view, is an attempt to explain the phenomena of experience and observation, and worthy in its own right, but it is ultimately incapable of dealing with questions of ultimate reality.

A good introduction to these two profound thinkers, I think, is their thoughts concerning substance. Both agreed that the Cartesian account of substance was logically flawed (if substance is supposed to be the most basic and self-sustaining constituent of the universe, and matter is extended through space, then matter could not be a basic substance, since it is infinitely divisible). They also agreed that Descartes' substance dualism was incapable of explaining the interaction of mind and body.

Their attempts to solve these theoretical difficulties eventually led them to postulate strange and fascinating views about the nature of reality that could hardly have been more different. For Spinoza, everything in nature, including God, is one: multiplicity is an appearance and God cannot stand outside of the natural world, since God is infinite by definition, and an infinite being cannot exist separately from anything that exists (else, He would not be infinite).

For Leibniz, on the other hand, the universe expresses God's infinite wisdom precisely through multiplicity and the unfolding of a pre-established harmony, set up by God, of course, between efficient and final causes. If you have no idea what I'm talking about, philosophers Anthony Quinton and Bryan Magee are here to explain the depth and intellectual influence of these two great thinkers.

And if you're wondering whether these philosophers actually matter, just consider that the very fact you're watching this on a computer or iphone can be traced back directly to Leibniz, since he invented the binary system upon which computation is based...

Check out more fascinating discussions about Plato, Aristotle, Hegel & Marx, Schopenhauer, and others in the Bryan Magee tag.