“What Makes You So Sure?” by Adam Kirsch. The New Yorker, 9/5/2016 (a book review of The Dream Of Enlightenment by Anthony Gottlieb).
(This has been sitting in my backup pile for quite a while. I thought no one would want to read it, but you are reading it right now.)
The first of the modern philosophers were not classified as philosophers in their day. Descartes and Leibniz were mathematicians. Spinoza ground lenses. Locke was a physician. Hume was a literary writer. According to Gottlieb, philosophy never seems to make any progress because “Any corner of it that comes generally to be regarded as useful soon ceases to be called philosophy.”
Today, we consider the philosophy of the 17th and 18th centuries (the Age of Enlightenment) as a struggle between the rationalists and empiricists, that is, whether truth is to be found internally by logic and reasoning, or by observation of the world. Late in the 18th century, Kant showed that both are correct, since all perception is filtered through categories imposed by our minds.
(My favorite example of Kant’s categories is the function of the heart. Before Galen, most guessed it was a furnace that heated the body, although physicians and butchers must have seen it still beating and squirting blood. But the pump had not yet been invented, so we had no category to define it.)
Kant lived in tumultuous times, and philosophy thrives when everything is up in the air, everything is being questioned. In just a few generations, every fixed point that oriented the world for thousands of years began to wobble.
The questions raised in the 18th century went to the heart of philosophy: What does it mean for something to be? Why does anything exist at all? Is there a God? These questions, as fundamental as they are, seemed useless speculation to practical people. Such questions had long disappeared from their consciousness, and when brought up, only irritated. Socrates, who asked, was put to death. Ask anyone today if there is life after death, and you will uncover a lot of irritation. Many will want you to see for yourself.
Descartes, a mathematician, described reality in terms of qualities that can be measured mathematically. Anything else must be assumed to be a delusion until proven otherwise, even our own existence. Descartes is the one who said, in the ultimate reduction, “I think, therefore I am.” (He questioned how he could prove he existed at all. Finally, after all of the approaches failed, the only one left was that he thinks.)
Mathematics is so seductive because each step follows inevitably from the one before, making the conclusion seem absolutely beyond doubt. Descartes even thought philosophy would not be studied after him because he solved all of the problems, but he never solved the problem of how mind and matter interact. He thought the pineal gland (a small gland deep in the brain) was the point of connection, but he was unclear about how this worked.
Leibniz tackled the problem of the mind and matter interaction by saying they don’t. Everything that exists, he reasoned, is made up of independent “monads” that have no way of communicating with one another. The world only appears to be a series of causes and effects because the monads are programmed to appear as if they interact. This programming was preestablished by a beneficent God.
Even his fellow philosophers could not swallow that, but scientists are still puzzled how consciousness can arise from the physical connections of the brain. And now we explain the universe by string theory that claims every particle of matter, every force, is composed of strings vibrating in many dimensions. [String theory does not actually say that. It only says the variety of subatomic particles can be explained by the same equations that govern the harmonics of vibrating strings in many dimensions. Maybe they really are vibrating strings, maybe not. But does it matter?]
Then, as today, all of these inexpiable observations are what we mean by “God.”
Bernard Spinoza came up with the idea of God so radical that his name became synonymous with atheism. But he did not deny God. He only said that God is so crucial to the world that they cannot be separated. Talking about God as distinct from Nature is ridiculous.
Spinoza is said to be the father of Biblical criticism. He held that the Bible was a human document that held no privileged information of the divinity. It should be read just like any other secular book, accounting for the motives of the writers and for errors that have accumulated over the years.
If, as Spinoza says, everything is God, and God is absolute (the Hindu belief of Brahman), then nothing can happen any differently that it does, and the seemingly random movement of a leaf blowing in the wind is as fixed as any function in a mathematical equation. There can be no free will.
Spinoza was no wild-eyed radical. His kindness and character were legendary. Bertrand Russell described him as “the noblest and most lovable of the great philosophers.”
The Brits favored their own philosophers: Thomas Hobbs, John Locke, and David Hume, who rejected deductive reasoning in favor of practical experience. This difference between British and European thinking still exists today (as I well know from working for a British company).
The biographer Boswell visited Hume on his deathbed, hoping he would embrace Christianity at the end, but Hume affirmed that “it is a most unreasonable fancy that we should exist forever.”