even by the Mind imagined by Laplace, if it made due use of its universal formula.
Now, suppose we had such astronomical knowledge as this, with regard to a muscle, a gland, an electrical organ, or a luminiferous organ in the state of excitation; of a ciliary cell, a plant, an ovum in contact with the sperm, or of a fruit at some stage of its development. In that case we should possess the fullest possible knowledge of these material systems, and our instinct of causality would be so far satisfied that we should desire nothing more, save to know what matter and force themselves are. Muscular contraction, secretion by the gland, the shock of the electrical, and the shining of the luminiferous organ; ciliary action, growth and chemical action of the cell in the plant; impregnation and development of the egg—all these phenomena, now hopelessly obscure, would be as evident for us as the movements of the planets. On the contrary, if we make a like supposition of astronomical knowledge, with regard to the brain of man, or even the soul-organ of the lowest animal, whose mental activity may be restricted to the sensation of pleasure and pain, then, so far as all the material phenomena are concerned, our knowledge would be as perfect, and our instinct of causality as satisfied, as in the case of muscular contraction or secretion, provided we had astronomical knowledge of muscles or glands. The involuntary actions of the centres, and those not necessarily connected with sensation—reflex action, simultaneous action, respiratory movements, growth and decay of the brain and spinal cord—would be completely understood. Further, those phenomena which are always, and hence necessarily, simultaneous with mental phenomena, would also be perfectly understood. And it certainly were a great triumph of human knowledge if we were able to say that, on occasion of a given mental phenomenon, a certain definite motion of definite atoms would occur in certain definite ganglia and nerves. It would be profoundly interesting if we could thus, with the mind's eye, note the play of the brain-mechanism, in working out a problem in arithmetic, after the manner of a calculating-machine; or, even if we could say what play of the carbon, hydrogen, nitrogen, oxygen, phosphorus, and other atoms, corresponds to the pleasure we experience on hearing musical sounds; what whirl of such atoms answers to the climax of sensual enjoyment; and what molecular storm to the raging pain we feel when the trigeminus nerve is misused. The intellectual enjoyment afforded by Fechner's preliminary studies in psychophysics, and by Donders's measurements of the duration of simpler mental operations, gives reason to expect that such direct insight into the material conditions of mental phenomena would be highly instructive.
Still, as regards mental operations themselves, it is clear that, even with astronomical knowledge of the mind-organ, they would be as unintelligible as they are now. Were we possessed of such knowledge,