these substances that translate the identical excitation of all the nerves into sense-perceptions, each set, according to its own nature, acting as carriers of Joh. Müller's "specific energies," and so giving quality. The Mosaic dictum, "There was light," is physiologically false. Light first was when the first red eye-point of an infusorial animal for the first time distinguished light from darkness. In the absence of the sense-substance of sight and hearing, this bright, glowing, resonant world around us would be dark and voiceless.
And voiceless and dark in itself, i. e., property-less, as the universe is on subjective decomposition of the phenomena of sense, so is it also from the mechanical stand-point, gained by objective contemplation. Here, in place of sound and light, we have only the vibrations of a primitive, undifferentiated matter, which here has become ponderable, and there imponderable.
But, however well grounded these views may be in general, nothing, as we may say, has been done toward carrying them out in detail. The philosopher's stone that should transmute into one another the as yet unanalyzed elements, and produce them from a higher element, if not from primeval matter itself, must be discovered before the first conjecture as to the development of apparently heterogeneous, from actually homogeneous matter, becomes possible.
Though the human mind will ever remain very remote from the mind imagined by Laplace, yet this is only a matter of degree, in some measure like the difference between a given ordinate of a curve and another immeasurably greater, though still finite, ordinate of the same curve. We resemble this mind, inasmuch as we conceive of it. We might even ask whether a mind like that of Newton does not differ less from the mind imagined by Laplace, than the mind of an Australian or of a Fuegian savage differs from the mind of Newton. In other words, the impossibility of stating and integrating the differential equations of the universal formula, and of discussing the result, is not fundamental, but rests on the impossibility of getting at the necessary determining facts, and, even where this is possible, of mastering their boundless extension, multiplicity, and complexity.
Thus the knowledge of Nature possessed by the mind imagined by Laplace, represents the highest thinkable grade of our own natural science. Hence we may lay this down as the basis of our inquiry as to the limits of this science. Whatever would remain unknown to such a mind, must be perfectly hidden away from our minds, which are confined within much narrower bounds.
There are two positions where even the mind imagined by Laplace would strive in vain to press on farther, and where we have to stand stock-still.
In the first place we must observe that the knowledge of Nature already spoken of as provisionally satisfying our desire of tracing things to their causes, in reality does no such thing, and is not
