Who Was Baruch Spinoza? Expelled at Twenty-Three, Read Ever Since

Born in Amsterdam in 1632 to a family of Portuguese Jews who had fled the Inquisition, he was educated in the community's school, learned Hebrew and the rabbinic tradition, and also studied Latin, Descartes and the new natural philosophy with a former Jesuit. What exactly provoked the expulsion is not recorded, and the likeliest account is that he had already reached views about God, scripture and the soul that the community, itself precariously tolerated in a Calvinist republic, could not afford to be associated with. He took the Latin name Benedictus, moved between Rijnsburg, Voorburg and The Hague, and supported himself grinding optical lenses, a skilled trade connected to the telescope and microscope work of the period and one that probably contributed to his death from a lung illness at forty-four. He declined a chair at Heidelberg in 1673 on the grounds that the freedom to philosophise it offered came with a condition not to disturb the established religion, which he judged unworkable.

His metaphysics begins from definitions and proceeds by numbered propositions, each with a demonstration, in imitation of Euclid, which makes his major work the most formally structured in the history of philosophy and among the hardest to read. The argument runs roughly like this. A substance is something that exists in itself and is conceived through itself, needing nothing else to be understood. Two substances could not interact or limit each other without one depending on the other, so there can be only one substance, which is infinite and self-caused, and which he calls God or Nature, treating the two words as naming the same thing. Everything else, every mind and body and event, is not a separate thing but a mode, a particular way in which that one substance is modified, in the way a wave is a way the sea is behaving rather than an object sitting on it. Thought and extension, mind and matter, are two of the infinite attributes through which the one substance is expressed, which dissolves Descartes's problem of how mind and body interact by denying that they are two things at all.

The consequences horrified almost everyone who read him:

• •God is not a person, has no will, no purposes, no preferences and does not act for ends, since acting for an end implies lacking something
• •There are no miracles, because a miracle would be nature violating its own necessity, which is incoherent
• •Nothing is contingent: everything that happens follows necessarily from the nature of the one substance, so the universe could not have been otherwise
• •Free will is an illusion produced by our being conscious of our desires and ignorant of their causes, which he illustrates by saying a stone in flight would believe itself free if it could think
• •Good and evil are not properties of things but relations to us, so a thing is good insofar as it is useful to our nature
• •The mind is the idea of the body, so mental and physical events are the same events described under different attributes rather than two sets of events causally connected

The title of his major work is misleading if it suggests rules of conduct, since the metaphysics occupies most of it and the practical upshot is a therapy rather than a code. Human unhappiness, on his account, comes from the passions, which are states in which we are acted upon by external causes we do not understand, and from which we can be freed only by understanding them, since an emotion ceases to be a passion as soon as we form a clear idea of its cause. The aim is to move from being driven by inadequate ideas to acting from adequate ones, which is what he means by freedom: not escaping necessity, which is impossible, but grasping it. The highest state he describes is an intellectual love of God, meaning a rational understanding of the necessity of everything, which is not devotion to a person and is closer to the attitude of a scientist who finds the structure of the world intelligible. The closing line of the book notes that everything excellent is as difficult as it is rare.

The one substantial work published in his lifetime, anonymously in 1670, is the Theological-Political Treatise, and it did two things nobody had done so directly. It read the Bible as a historical document written by particular people for particular audiences, examining its language, contradictions and authorship, which makes him a founder of modern biblical criticism. And it argued for freedom of thought and expression as necessary to a stable state, on the grounds that belief cannot be compelled and that attempts to control it produce hypocrisy and rebellion, an argument made a century before the American and French constitutions. The book was banned and denounced across Europe, and Spinozism became the standard term of abuse for atheism for a hundred years. The rehabilitation came in Germany in the late eighteenth century, when a public controversy over whether Lessing had been a Spinozist made him unavoidable, and Goethe, Coleridge, Hegel, Einstein, who said explicitly that he believed in the God of Spinoza, and a long line since have taken him as central rather than scandalous.

Expelled from the Amsterdam Jewish community at twenty-three for reasons never recorded, he ground lenses, declined a professorship and argued in geometric form that there is only one substance, which he called God or Nature, of which everything else is a passing mode. That makes God impersonal and purposeless, miracles impossible, everything necessary and free will an illusion. His practical ethics is a therapy in which understanding a passion's cause dissolves it, and his political treatise founded biblical criticism and argued early for freedom of expression.