And if by selecting the atomic theory as an example he has chosen one upon which supplementary and most interesting facts have been grafted in the progress of discovery—facts not really contradicting the old knowledge, even when superficially appearing to do so, but adding to it and illuminating it further, while making changes perhaps in its manner of formulation—he has chosen such an example of set purpose, as not unlikely to be imitated in the present case also.
CHAPTER I
THE MEANING OF THE TERM LIFE
"Eternal process moving on."—Tennyson
THE shorter the word the more inevitable it is that it will be used in many significations; as can be proved by looking out almost any monosyllable in a large dictionary. The tendency of a simple word to have many glancing meanings—like shot silk, as Tennyson put it—is a character of high literary value; though it may be occasionally inconvenient for scientific purposes. It is unlikely that we can escape an ambiguity due to this tendency, but I wish to use the term 'life' to signify the vivifying principle which animates matter.
That the behaviour of animated matter differs from what is often called dead matter is familiar, and is illustrated by the description sometimes given of an uncanny piece of mechanism—that "it behaves as if it were alive." In the case of a jumping bean, for instance, its spasmodic and capricious behaviour can be explained with apparent simplicity, though with a suspicious trend towards superstition, by the information that a live and active maggot inhabits a cavity inside. It is thereby removed from the bare category of physics only, though still perfectly obedient to physical laws: it jumps in accordance with mechanics, but neither the times nor the direction of its jumps can be predicted.[32]
We must admit that the term 'dead matter' is often misapplied. It is used sometimes to denote merely the constituents of the general inorganic world. But it is inconvenient to speak of utterly inanimate things, like stones, as 'dead,' when no idea of life was ever associated with them, and when 'inorganic' is all that is meant. The term 'dead' applied to a piece of matter signifies the absence of a vivifying principle, no doubt, but it is most properly applied to a collocation of organic matter which has been animated.
Again, when animation has ceased, the thing we properly call dead is not the complete organism, but that material portion which is left behind; we do not or should not intend to make any assertion concerning the vivifying principle which has left it,—beyond the bare fact of its departure. We know too little about that principle to be able to make safe general assertions. The life that is transmitted by an acorn or other seed fruit is always beyond our ken. We can but study its effects, and note its presence or its absence by results.
Life must be considered sui generis; it is not a form of energy, nor can it be expressed in terms of something else. Electricity is in the same predicament; it too cannot be explained in terms of something else. This is true of all fundamental forms of being. Magnetism may be called a concomitant of moving electricity; ordinary matter can perhaps be resolved into electric charges: but an electric charge can certainly not be expressed in terms of either matter or energy. No more can life. To show that the living principle in a seed is not one of the forms of energy, it is sufficient to remember that that seed can give rise to innumerable descendants, through countless generations, without limit. There is nothing like a constant quantity of something to be shared, as there is in all examples of energy: there is no conservation about it: the seed embodies a stimulating and organising principle which appears to well from a limitless source.