Contemporaneous with Isaac Baer Levinsohn, and hardly less distinguished and influential, was Mordecai Aaron Guenzburg (ReMAG, Salanti, Kovno, December 3, 1795--Vilna, November 5, 1846). His family had been prominent in many walks of life since the fourteenth century, and, whether in the land of the Saxons or of the Slavs, represented the cream of the Jewries in which they lived. His father was a Maskil of great repute, who had written several treatises, in Hebrew, on algebra, geometry, optics, and kindred subjects. He sought to supplement his son Mordecai Aaron's heder education with a knowledge of secular sciences. But at that time and in that place not many were the books, outside the Talmud, accessible to a lad eager for learning, the only ones available being such as the _Josippon_, _Zemah David_, and _Sheerit Yisrael_ on Jewish History, the _Sefer ha-Berit_, and a Hebrew translation of Mendelssohn's _Phaedon_ on general philosophy. But the precocious and clear-minded youth did not need much to stimulate his love for history and his inclination to philosophy, and his intellectual development continued in spite of the untoward circumstances in which he happened to be placed. Though he was "given" in marriage at a very early age, the proverbial "millstone" weighed but lightly upon the neck of young Guenzburg. He never discontinued the habit of secluding himself in his study for hours, sometimes for days, at a time, and there writing down his thoughts in painstaking penmanship. These productions, with all their crudity, promised, according to a keen critic, the flowers which would one day "ripen into delicious fruit, not only pleasant to the sight but also delicious to the taste." In fact, even his religious views underwent but slight modification in later and maturer years. Ceremonial laws, or minhagim, were to him a social compact among the members of a sect. He who transgresses them is, _eo ipso_, excluded from the sect, as he who disregards the social code, though not immoral, is ostracized from society. This led him to the logical conclusion that every Jew must comply with the customs of his people, though his opinion as to their moral value may differ from that of the rest. He believed in freedom of thought, but would not concede freedom of action or even of expression, and would say with Bolingbroke, "Freedom belongs to a man as a rational creature, he lies under the restraint as a member of society."