Can any one doubt that if the noblest saint among the Buddhists, the best Mahometan, the highest Stoic of Athens, the purest and wisest Christian, — … - Benedictus de Spinoza

His [Spinoza's] correspondence is the most interesting book one can read in the world of uprightness and of humanity. [Original in German: Sei Briefwechsel sei das interessanteste Buch, das man in der Welt von Aufrichtigkeit, Menschenliebe lesen könne.]

He supported himself by grinding lenses, which was no lowly menial occupation, as it is often presented to have been in romanticizing versions of the philosopher's life, but was rather a craft that drew extensively from Spinoza's serious interest in the science of optics. The quality of his wares was highly valued by other scientists of his day. The important Dutch astronomer Christiaan Huygens, who discovered Saturn's rings as well as one of its four moons, preferred Spinoza's lenses to all others. "The [lenses] that the Jew of Voorburg has in his microscopes have an admirable polish," Huygens wrote to his brother in 1667. The one part of the romantic lens-grinding legend that is sadly true is that the dust from the optical polishing was unhealthy for Spinoza, whose mother and brother had both died young from tuberculosis. He himself succumbed to the disease at the age of forty-four.

We have thus begun to think of Spinoza's "radicalism" differently than the past century did. Now we see that the bold innovations of Spinoza were only consequences, rather than foundations. The fact that now gains in importance is that — compared to the significance of Descartes, Hobbes, and Leibniz — Spinoza is only of secondary significance in the history of the core sciences, that is, in the history of natural science, on the one hand, and of natural right, on the other. And the fact that Spinoza achieved more general recognition only toward the end of the eighteenth century is now also understandable: he could be accepted only at the moment when the "querelle des anciens et des modemes" within philosophy had been decided on the main point in favor of the moderns, and when what mattered was the restoration, for the purpose of correcting the modern idea, of certain positions of the premodern world that had been knocked over in the first onslaught; for Spinoza — who stood on the foundation of modern philosophy laid by Descartes and Hobbes — had carried along into the modern world, which he already found in existence, the ideal of life of the premodern (ancient-medieval) tradition, the ideal of the (theoretical) knowledge of God.