I believe in Spinoza's God, who reveals himself in the lawful harmony of the world, not in a God who concerns himself with the fate and the doings of… - Benedictus de Spinoza

يظن الناس أنفسهم أحرارًا لأنهم شاعرون بإرادتهم ورغباتهم، ولكنهم يجهلون الأسباب التي أفضت بهم إلى الإرادة والرغبة

But orthodox religious scholasticism, in alliance with subjective idealist philosophy, has not ceased to flog Spinoza as a ‘dead dog’, treating him as a living and dangerous opponent. Elementary analysis reveals that the main principles of Spinoza’s thought directly contradict the conception of ‘thought’ developed by modern positivism all along the line. The most modern systems of the twentieth century still clash in sharp antagonism in Spinoza; and that obliges us to analyse the theoretical foundation of his conception very carefully, and to bring out the principles in it that, in rather different forms of expression perhaps, remain the most precious principles of any scientific thinking to this day, and as such are very heatedly disputed by our contemporary opponents of dialectical thought.

I believe we can guess at the first time Einstein read Baruch Spinoza's Ethics (Ethica Ordinae Geometrico Demonstrata), a system constructed on the Euclidean model of deductions from propositions. Soon after getting his first real job at the patent office, Einstein joined with two friends to form a discussion circle, meeting once or twice a week in what they called, with gallows humor, the Akademie Olympia. We know the list of books they read and discussed. High among them, reportedly at Einstein's suggestion, was Spinoza's Ethics, which he read afterwards several times more. Even when his sister Maja joined him in Princeton in later life and was confined to bed by an illness, he thought that reading a good book to her would help, and chose Spinoza's Ethics for that purpose. By that time Spinoza's work and life had long been important to Einstein. He had written an introduction to a biography of Spinoza (by his son-in-law, Rudolf Kayser, 1946); he had contributed to the Spinoza Dictionary (1951); he had referred to Spinoza in many of his letters; and he even had composed a poem in Spinoza's honor. He admired Spinoza for his independence of mind, his deterministic philosophical outlook, his skepticism about organized religion and orthodoxy – which had resulted in his excommunication from his synagogue in 1656 – and even for his ascetic preference, which compelled him to remain in poverty and solitude to live in a sort of spiritual ecstasy, instead of accepting a professorship at the University of Heidelberg.