Baruch or Benedict Spinoza was born at Amsterdam, Nov. 24, 1632. His parents were Jews of Portuguese descent, and being merchants of opulence, they gave him a finished education. He studied with great diligence the Bible and the Talmud, but soon exchanged the pursuit of theology for the study of physics and the works of Descartes. He early became dissatisfied with Judaism, and presently came to an open rupture with it, though without going over formally to Christianity. In order to escape the persecutions of the Jews, who had excommunicated him, and who even went so far as to make an attempt upon his life, he left Amsterdam and betook himself to Rhynsberg, near Leyden. He finally settled down at the Hague, where he spent his life in the greatest seclusion, devoted wholly to scientific pursuits. He supported himself by grinding optic glasses, which his friends sold for him. The Elector Palatine, Charles Louis, offered him a Professorship of Philosophy at Heidelberg, with the full permission to teach as he chose, but Spinoza declined the post. Naturally of a weak constitution, which consumption had for many years been undermining, Spinoza died at the age of 44, on the 21st of February, 1677. In his life there was mirrored the unclouded clearness and exalted serenity of the perfected sage. Abstemious in his habits, satisfied with little, the master of his passions, never intemperately sad nor joyous, gentle and benevolent, with a character of singular excellence and purity, he faithfully illustrated in his life, the doctrines of his philosophy. His chief work, the _Ethica_, appeared the year of his death. His design was probably to have published it during his life, but the odious report that he was an atheist restrained him. The friend he most trusted, Louis Mayer, a physician, attended to its publication after the author’s death and according to his will. The system of Spinoza rests upon three fundamental conceptions, from which all the rest may be derived with mathematical necessity. These conceptions are that of substance, of attribute, and of mode.