materials of such unequal solidity reminds one of those dilapidated Gothic churches which brainless masons used to patch up with a plaster of soot and cheese, giving it, by means of a wash, the appearance of stone. To the eye the frontage is irreproachable, but many parts of the building could not for one moment resist a vigorous blow of criticism. Many erroneous explanations of natural phenomena, the majority of false scientific hypotheses, all religious and metaphysical systems, have arisen in such a way that mankind, in their thoughts and opinions, have interwoven, as equally valid components, ideas suggested by words only, together with such as were derived from direct perception. The words were either invented by mystics and originally indicated nothing beyond the unbalanced condition of a weak and diseased brain, or, whereas they at first expressed a definite, correct presentation, their proper meaning was not caught by those who repeated them, and by them was arbitrarily falsified, differently interpreted, or blurred. Innate or acquired weakness of mind and ignorance lead alike to the goal of mysticism. The brain of the ignorant elaborates presentations that are nebulous, because they are suggested by words, not by the thing itself, and the stimulus of a word is not strong enough to produce vigorous action in the brain-cells; moreover, the brain of the exhausted and degenerate elaborates nebulous presentations, because in any case it is not in a condition to respond to a stimulus by vigorous action. Hence ignorance is artificial weakness of mind, just as, conversely, weakness of mind is the natural organic incapacity for knowledge.