Baruch Spinoza

Spinoza was expelled from the Amsterdam Jewish community at twenty-three, in one of the most savage excommunications on record, for opinions he had not yet even published. He spent the rest of his life grinding lenses for a living (the dust eventually killed him) and writing the most uncompromising metaphysical system in modern philosophy.

His Ethics, published after his death, is laid out like Euclid's Elements: definitions, axioms, propositions, demonstrations. The conclusion: there is exactly one substance, and you can call it either God or Nature. Everything that exists is a mode of this single substance. Mind and body are not two things; they are one thing seen under two attributes. Free will is an illusion. Salvation is the intellectual love of God – meaning, the understanding of one's own necessary place in the infinite causal order.

He was called the great atheist of his age. He was called the God-intoxicated philosopher. Goethe, Einstein, Borges, and George Eliot all loved him for the same reasons.