And here I must mention a startling discovery, the most startling, it seems to me, of recent times. It is that these laws of human thought are frightfully rigid, are indeed automatic and inflexible. The human mind seems to be a machine; give it the same materials, and it will infallibly grind out the same product. So deeply impressed by this is an eminent modern writer that he lays it down as “a fundamental maxim of ethnology” that, “we do not think; thinking merely goes on within us.”[4] These strange coincidences find their explanation in experimental psychology. This science, in its modern developments, establishes the fact that the origin of ideas is due to impressions on the nerves of sense. The five senses give rise to five classes of ideas, the most numerous of which are those from the sense of sight, visual ideas, and those from the sense of hearing, auditory ideas. The former yield the conceptions of space, motion, and lustre (colour, brightness, etc.), the latter that of time. From the sense of touch arise the “tactual” impressions, which yield the ideas of power and might, through the sensations of resistance and pressure, pleasure and pain. From these primary ideas (or perceptions), drawn directly from impressions, are derived secondary, abstract, and general ideas (apperceptions) by comparison and association (the laws of Identity, Diversity, and Similarity). Under ordinary conditions of human life there are many more impressions on the senses which are everywhere the same or similar, than the reverse. Hence, the ideas, both primary and secondary (perceptions and apperceptions), drawn from them are much more likely to resemble than to differ. The consequence of this is that the same laws of growth which develop the physical man everywhere into the traits of the species, act also on his psychical powers, and not less absolutely, to bring their products into conformity. This is true not only of his logical faculties, but of his lightest fancies and wildest vagaries. “Man’s imagination,” observes Mr. Hartland, “like every other known power, works by fixed laws, the existence and operation of which it is possible to trace; and it works upon the same material,—the external universe, the mental and moral constitution of man, and his social relations.”[5] In reference to my particular subject, Professor Buchmann expressed some years ago what I believe to be the correct result of modern research in these words: “It is easy to prove that the striking similarity in primitive religious ideas comes not from tradition nor from the relationship or historic connections of early peoples, but from the identity in the mental construction of the individual man, wherever he is found.”[6]