On July 27, 1656, the Portuguese-Jewish community of Amsterdam issued the most severe cherem, excommunication, in its history. The target was Baruch Spinoza, a twenty-three-year-old lens grinder. The document cursed him with every curse in the Book of the Law, banned all contact with him, and forbade anyone from reading his writings or standing within four cubits of him. He was not yet a philosopher. He was not yet famous. He was just a young man who had said things about God that the community could not tolerate. He accepted the excommunication without protest and spent the rest of his life grinding lenses and writing philosophy. He never joined another religious community. He never complained about the injustice. He just kept thinking.

The God That Is Everything and Wants Nothing

Spinoza's central claim is breathtaking in its simplicity. God and Nature are the same thing. There is only one substance in the universe, and that substance is infinite, eternal, and self-caused. Everything that exists, every rock, every thought, every human body, is a modification of this single substance. God is not a person who created the world. God is the world. Philosophers at the University of Leiden, where Spinoza's manuscripts are preserved, have described the Ethics, his masterwork, as one of the most ambitious philosophical systems ever constructed. It is written in the geometric method, modeled on Euclid's Elements, with definitions, axioms, propositions, and proofs. Spinoza did not argue for his position. He attempted to demonstrate it with the rigor of a mathematical proof. Here is the thing that made this so explosive. If God is everything, then God does not have preferences. God does not choose one people over another. God does not answer prayers. God does not punish sinners or reward the faithful. The entire structure of organized religion, the intermediaries, the rituals, the hierarchies, becomes unnecessary. Spinoza did not attack religion directly. He simply described a universe in which religion had no function, which was considerably more devastating.

The Lens Grinder Who Chose Poverty Over Compromise

Spinoza could have been comfortable. He was offered a professorship at the University of Heidelberg on the condition that he not disturb the established religion. He declined, politely, saying he could not determine where the boundaries of that condition would lie and that it would interfere with his freedom of thought. He ground lenses instead. The dust from the grinding is believed to have contributed to the lung disease that killed him at forty-four. Researchers at the Spinoza Centre in Amsterdam have documented that he lived in modest rented rooms for most of his adult life. He had a small circle of correspondents and friends. He published the Tractatus Theologico-Politicus anonymously in 1670 and the Ethics was published posthumously in 1677. He did not seek fame. He did not seek approval. He sought clarity, and he was willing to pay for it with everything else. The lens grinding was not just a livelihood. It was a metaphor that Spinoza would have appreciated. He spent his life trying to see more clearly, and he made his living by improving other people's ability to see.

He Was Centuries Ahead and He Knew It

Spinoza's influence was slow-burning but enormous. Hegel called him the starting point of all modern philosophy. Einstein, when asked if he believed in God, said he believed in Spinoza's God. Researchers at Columbia University's Department of Philosophy have traced Spinoza's influence through the Enlightenment, German Idealism, and into contemporary philosophy of mind, where his dual-aspect monism, the idea that mind and body are two aspects of the same substance, anticipates several current theories of consciousness. He was reviled in his lifetime. He was called an atheist, a heretic, a threat to public morals. His books were banned in multiple countries. The communities that banned them eventually became the societies that were shaped by his ideas, which is the most Spinozan irony imaginable. I think about Spinoza when I think about the cost of intellectual honesty. He did not sacrifice comfort for fame. He sacrificed comfort for the right to think without restrictions. The lens grinder's room was small. The ideas that came out of it were not.