In the case of any new theory, it is true that one must live with it for a considerable time before acquiring the habit of thinking in accordance with it. The older habits constantly crop up and interfere with the correct understanding of any new point of view. This is especially so of a new attitude towards reality. The world seems topsy-turvy to one who learns for the first time that grass and the leaves of trees are not really green apart from the eye that sees them, that beings with different organs might interpret differently that which stimulates the human eye to its specific color reactions. The heliocentric theory, when first announced by Copernicus, outraged naïve commonsense. It exacted a new habit of thinking in regard to the relation of the sun to the earth,—the real relation, apprehended by intercalated mental processes being the direct opposite of the apparent relation. The sun evidently revolves around the earth, nevertheless the truth is that the earth revolves around the sun. Modern science reveals behind the palpable world around us unimaginable fluids, speeds, and physical units which are so sublimated in thought as to be barely distinguishable from metaphysical entities. The habit of penetrating with radium-like glance the concrete screen of things, and of seeing behind the screen the company of atoms, ions, etc., may be gradually acquired; but the older habit of regarding the palpable and visible as the truly real continues to assert itself in conflict with the new habit. The ethical unit in an ethical manifold postulated in the text as the closest, though still symbolic, reading of the ultimate reality, makes a similar demand upon the reader, and requires of him in like manner the formation of a new habit of thinking, against which the older habits will doubtless continue to protest. The most obstinate of the older habits that stand in the way has been dealt with in the note on causality, namely,—the unscientific habit of ignoring the boundaries of science, and of taking the method employed in the physical sciences as the sole method that leads to certainty. The prejudice of causality is probably ineradicable, just as the illusion that the sun revolves about the earth persists. But we can at least reach the point of realizing that it is a prejudice, and to this extent overcome it. If it be synthesis, or the employment in inseparable conjunction of the two functions mentioned, that for the human mind spells reality, then one kind of synthesis called causality, that of sequent phenomena, does not exclude the ampler, though ideal synthesis, which is carried out in the mental production of the ethical manifold. So much I wish to add to the statements contained in the text in regard to the theory.