_Indian Logic earlier than that of Aristotle._--It is of the Greek logic, that of Aristotle, that we usually speak when we have occasion to refer to this science. It is usually attributed to Aristotle, indeed, as his peculiar glory, that he should at once have originated, and brought to perfection, a science which, for more than two thousand years, has received few alterations, found few minds capable of suggesting improvements. Recent labors of Orientalists have, however, brought to light the fact that in India, long before the palmy days of Grecian philosophy, logic was pursued with vigor as a study and science. The Nyàya of Gotama holds, in the Indian systems of philosophy, much the same place that the Organon of Aristotle holds with us. The two, however, are quite independent of each other. Aristotle was no disciple of Gotama. _Aristotle's Logic not perfect._--Nor, on the other hand, was the logic of Aristotle by any means perfect, as it is often represented. Its imperfections are many, and have been, for the most part, faithfully copied by his disciples. _Aristotle the first Greek Logician._--Previous to Aristotle there had been nothing worthy the name of science in this department of philosophy. The Sophists had made some attempts at logic, but of no great value. Plato had not devoted much attention to it. Aristotle himself says, in the close of his Organon, that he had worked without models or predecessors to guide him. _Subsequent Writers._--The work of Aristotle is in six parts, the first four treating of logic pure, the remaining two of its application. The school of Aristotle carried the cultivation and study of logic to a high degree. Theophrastus and Eudemus labored assiduously as commentators on their master, but made no change in the essential principles of the system. The Stoics, however, gave logic more attention and honor, more time and care, than did any other of the rival schools of philosophy. They sought to enlarge its boundaries and make it an instrument for the discovery of truth. It held the first place in their system, ethics and physics ranking after it. St. Hilaire is wrong in saying that with Epicurus logic was of little consideration, that sensation was the source and criterion of thought with that school. The Epicurean logic was a peculiar system, differing from the Aristotelian, and very little known in the subsequent centuries. In Alexandria the logic of Aristotle was in great honor, and had numerous commentators in the first centuries of the Christian era.