That I might investigate the subject matter of this science with the same freedom of spirit we generally use in mathematics, I have labored carefully… - Benedictus de Spinoza

What can be more calamitous than that men should be regarded as enemies and put to death, not for any crime or misdeed, but for being of independent mind?

Homo liber de nulla re minus, quam de morte cogitat, et ejus sapientia non mortis, sed vitae meditatio est.

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.