To make intelligible the Transcendental Philosophy of the last generation in New England it is not necessary to go far back into the history of thought. Ancient idealism, whether Eastern or Western, may be left undisturbed. Platonism and neo-Platonism may be excused from further tortures on the witness stand. The speculations of the mystics, Romanist or Protestant, need not be re-examined. The idealism of Gale, More, Pordage, of Cudworth and the later Berkeley, in England, do not immediately concern us. We need not even submit John Locke to fresh cross-examination, or describe the effect of his writings on the thinkers who came after him. The Transcendental Philosophy, so-called, had a distinct origin in Immanuel Kant, whose "Critique of Pure Reason" was published in 1781, and opened a new epoch in metaphysical thought. By this it is not meant that Kant started a new movement of the human mind, proposed original problems, or projected issues never contemplated before. The questions he discussed had been discussed from the earliest times, and with an acumen that had searched out the nicest points of definition. In the controversy between the Nominalists, who maintained that the terms used to describe abstract and universal ideas were mere names, designating no real objects and corresponding to no actually existing things, and the Realists, who contended that such terms were not figments of language, but described realities, solid though incorporeal, actual existences, not to be confounded with visible and transient things, but the essential types of such,--the scholastics of either school discussed after their manner, with astonishing fulness and subtlety, the matters which later metaphysicians introduced. The modern Germans revived in substance the doctrines held by the Realists. But the scholastic method, which was borrowed from the Greeks, lost its authority when the power of Aristotle's name declined, and the scholastic discussions, turning, as they signally did, on theological questions, ceased to be interesting when the spell of theology was broken. Between the schools of Sensationalism and Idealism, since John Locke, the same matters were in debate. The Scotch as well as the English metaphysicians dealt with them according to their genius and ability. The different writers, as they succeeded one another, took up the points that were presented in their day, exercised on them such ingenuity as they possessed, and in good faith made their several contributions to the general fund of thought, but neglected to sink their shafts deep enough below the surface to strike new springs of water.