Entirely without assignable attributes, this something occurs in thought not as an idea but as a pseud-idea (First Principles, Chap. II). It is assumed to be representable while really unrepresentable. We need only insist on answers to certain questions to see that it is simply a name for an alleged existence which has not been conceived and cannot be conceived.
1. Is there one kind of vital principle for all kinds of organisms, or is there a separate kind for each? To affirm the first alternative is to say that there is the same vital principle for a microbe as for a whale, for a tape-worm as for the person it inhabits, for a protococcus as for an oak; nay more – is to assert community of vital principle in the thinking man and the unthinking plant. Moreover, asserting unity of the vital principle for all organisms, is reducing it to a force having the same unindividualized character as one of the physical forces. If, on the other hand, different kinds of organisms have different kinds of vital principles, these must be in some way distinguished from one another. How distinguished? Manifestly by attributes. Do they differ in extension? Evidently; since otherwise that which animates the vast Sequoia can be no larger than that which animates a yeast-plant, and to carry on the life of an elephant requires a quantity of vital principle no greater than that required for a microscopic monad. Do they differ otherwise than in amount? Certainly; since otherwise we revert to the preceding alternative, which implies that the same quality of vital principle serves for all organisms, simple and complex: the vital principle is a uniform force like heat or electricity. Hence, then, we have to suppose that every species of animal and plant has a vital principle peculiar to itself – a principle adapted to use the particular set of structures in which it is contained. But dare anyone assert this multiplication of vital principles, duplicating not only all existing plants and animals but all past ones, and amounting in the aggregate to some millions?
2. How are we to conceive that genesis of a vital principle which must go along with the genesis of an organism? Here is a pollen-grain which, through the pistil, sends its nucleus to unite with the nucleus of the ovule; or here are the nuclei of spermatozoon and ovum, which, becoming fused, initiate a new animal: in either case failure of union being followed by decomposition of the proteid materials, while union is followed by development. Whence comes that vital principle which determines the organizing process? Is it created afresh for every plant and animal? or, if not, where and how did it pre-exist? Take a simpler form of this problem. A protophyte or protozoon, having grown to a certain size, undergoes a series of complex changes ending in fission. In its undivided state it had a vital principle. What of its divided state? The parts severally swim away, each fully alive, each ready to grow and presently to subdivide, and so on and so on, until millions are soon formed. That is to say, there is a multiplication of vital principles as of the protozoa animated by them. A vital principle, then, both divides and grows. But growth implies incorporation of something. What does the vital principle incorporate? Is it some other vital principle external to it, or some materials out of which more vital principle is formed? And how, in either case, can the vital principle be conceived as other than a material something, which in its growth and multiplication behaves just as visible matter behaves?
3. Equally unanswerable is the question which arises in presence of life that has become latent. Passing over the alleged case of the mummy wheat, the validity of which is denied, there is experimental proof that seeds may, under conditions unfavourable to germination, retain for ten, twenty, and some even for thirty years, the power to germinate when due moisture and warmth are supplied. (Cf. Kerner's Nat. Hist. of Plants, i, 51-2). Under what form has the vital principle existed during these long intervals? It is a principle of activity. In this case, then, the principle of activity becomes inactive. But how can we conceive an inactive activity? If it is a something which though inactive may be rendered active when conditions favour, we are introduced to the idea of a vital principle of which the vitality may become latent, which is absurd. What shall we say of the desiccated rotifer which for years has seemed to be nothing more than a particle of dust, but which now, when water is supplied, absorbs it, swells up, and resumes those ciliary motions by which it draws in nutriment? Was the vital principle elsewhere during these years of absolute quiescence? If so, why did it come back at the right moment? Was it all along present in the rotifer though asleep? How happened it then to awaken at the time when the supply of water enabled the tissues to resume their functions? How happened the physical agent to act not only on the material substance of the rotifer, but also on this something which is not a material substance but an immaterial source of activity? Evidently neither alternative is thinkable.
Thus, the alleged vital principle exists in the minds of those who allege it only as a verbal form, not as an idea; since it is impossible to bring together in consciousness the terms required to constitute an idea. It is not even "a figment of imagination," for that implies something imaginable, but the supposed vital principle cannot even be imagined.
§ 36d. When, passing to the alternative, we propose to regard life as inherent in the substances of the organisms displaying it, we meet with difficulties different in kind but scarcely less in degree. The processes which go on in living things are incomprehensible as results of any physical actions known to us.
Consider one of the simplest – that presented by an ordinary vegetal cell forming part of a leaf or other plant-structure. Its limiting membrane, originally made polyhedral by pressure of adjacent cells, is gradually moulded "into one of cylindrical, fibrous, or tabular shape, and strengthening its walls with pilasters, borders, ridges, hooks, bands, and panels of various kinds" (Kerner, i, 43): small openings into adjacent cells being either left or subsequently made. Consisting of non-nitrogenous, inactive matters, these structures are formed by the inclosed protoplast. How formed? Is it by the agency of the nucleus? But the nucleus, even had it characters conceivably adapting it to this function, is irregularly placed; and that it should work the same effects upon the cell-wall whether seated in the middle, at one end, or one side, is incomprehensible. Is the protoplasm then the active agent? But this is arranged into a network of strands and threads utterly irregular in distribution and perpetually altering their shapes and connexions. Exercise of fit directive action by the protoplasm is unimaginable.
Another instance: – Consider the reproductive changes exhibited by the Spirogyra. The delicate threads which, in this low type of Alga, are constituted of single elongated cells joined end to end, are here and there adjacent to one another; and from a cell of one thread and a cell of another at fit distance, grow out prominences which, meeting in the interspace and forming a channel by the dissolution of their adjoined cell-walls, empty through it the endochrome of the one cell into the other: forming by fusion of the two a zygote or reproductive body. Under what influence is this action initiated and guided? There is no conceivable directive agency in either cell by which, when conditions are fit, a papilla is so formed as to meet an opposite papilla.
Or again, contemplate the still more marvellous transformation occurring in Hydrodictyon utriculosum. United with others to form a cylindrical network, each sausage-shaped cell of this Alga contains, when fully developed, a lining chromatophore made of nucleated protoplasm with immersed chlorophyll-grains. This, when the cell is adult, divides into multitudinous zoospores, which presently join their ends in such ways as to form a network with meshes mostly hexagonal, minute in size, but like in arrangement to the network of which the parent cell formed a part. Eventually escaping from the mother-cell, this network grows and presently becomes as large as the parent network. Under what play of forces do these zoospores arrange themselves into this strange structure?
Kindred insoluble problems are presented by animal organisms of all grades. Of microscopic types instance the Coccospheres and Rhabdospheres found in the upper strata of sea-water. Each is a fragment of protoplasm less than one-thousandth of an inch in diameter, shielded by the elaborate protective structures it has formed. The elliptic coccoliths of the first, severally having a definite pattern, unite to form by overlapping an imbricated covering; and of the other the covering consists of numerous trumpet-mouthed processes radiating on all