Herbert Spencer

“ The definite combination of heterogeneous changes, both simultaneous and successive, is a formula which fails to call up an adequate conception. And it fails from omitting the most distinctive peculiarity—the peculiarity of which we have the most familiar experience, and with which our notion of Life is, more than with any other, associated. ”

“ On contemplating afresh our two typical phenomena, we may see that vital change is further distinguished from non-vital change, by being made up of many simultaneous changes. Nutrition is not simply a series of actions, but includes many actions going on together. ”

“ Consequently, when we attempt to define anything complex, or make a generalization of facts other than the most simple, we can scarcely ever avoid including more than we intended, or leaving out something which should be taken in. Thus it happens that on seeking a definite idea of Life, we have great difficulty in finding one that is neither more nor less than sufficient. ”

“ The definition of Richerand,—"Life is a collection of phenomena which succeed each other during a limited time in an organized body,"—is liable to the fatal criticism, that it equally applies to the decay which goes on after death. ”

“ A glacier may be instanced as showing nearly as much combination in its change as a plant of the lowest organization. It is ever growing and ever decaying; and the rates of its composition and decomposition preserve a tolerably constant ratio. It moves; and its motion is in immediate dependence on its thawing. It emits a torrent of water, which, in common with its motion, undergoes annual variations as plants do. During part of the year the surface melts and freezes alternately; and on these changes depend the variations in movement, and in efflux of water. ”

“ Though the states of consciousness which make up an argument occur in series, yet, as each of them is complex, a number of simultaneous changes have taken place in establishing it. Here as before, however, it must be admitted that the distinction between animate and inanimate is not precise. No mass of dead matter can have its temperature altered, without at the same time undergoing an alteration in bulk, and sometimes also in hygrometric state. An inorganic body cannot be compressed, without being at the same time changed in form, atomic arrangement, temperature, and electric condition. ”

“ As it at present stands, the definition is defective both in allowing that there may be other definite combinations of heterogeneous changes, and in directing attention to the heterogeneous changes rather than to the definiteness of their combination. Just as it is not so much its chemical elements which constitute an organism, as it is the arrangement of them into special tissues and organs; so it is not so much its heterogeneous changes which constitute Life, as it is the co-ordination of them. Observe what it is that ceases when life ceases. ”

“ This definition has some advantages. It includes all organic changes, alike of the viscera, the limbs, and the brain. It excludes the great mass of inorganic changes; which display little or no co-ordination. By making co-ordination the specific character of vitality, it involves the truths, that an arrest of co-ordination is death, and that imperfect co-ordination is disease. Moreover, it harmonizes with our ordinary ideas of life in its different grades; seeing that the organisms which we rank as low in their degrees of life, are those which display but little co-ordination of actions ”

“ Yet when we observe that very few inorganic objects manifest heterogeneity of change comparable to that manifested by organic objects, and further, that in ascending from low to high forms of life, we meet with an increasing variety in the kinds of changes displayed ”

“ And the reality of this distinction becomes yet more manifest when we find that, in common with previous ones, it not only marks off the living from the not-living, but also things which live little from things which live much. ”

“ It may turn out that to find a formula which will bear every test is impossible. Meanwhile, it is possible to frame a more adequate formula than any of the foregoing. As we shall presently find, these all omit an essential peculiarity of vital changes in general—a peculiarity which, perhaps more than any other, distinguishes them from non-vital changes. Before specifying this peculiarity, however, it will be well to trace our way, step by step, to as complete an idea of Life as may be reached from our present stand-point ”

“ And in a vast and mobile aggregate like the sea, the simultaneous as well as the successive changes outnumber those going on in an animal. Nevertheless, speaking generally, a living thing is distinguished from a dead thing by the multiplicity of the changes at any moment taking place in it. Moreover, by this peculiarity, as by the previous one, not only is the vital more or less clearly marked off from the non-vital; but creatures possessing high vitality are marked off from those possessing low vitality. ”

“ Inorganic changes, however, do not in any considerable degree exhibit this peculiarity. It is true that from meteorologic causes, inanimate objects are daily, sometimes hourly, undergoing modifications of temperature, of bulk, of hygrometric and electric condition. Not only, however, do these modifications lack that conspicuousness and that rapidity of succession which vital ones possess, but vital ones form an additional series. Living as well as not-living bodies are affected by atmospheric influences ”

“ To those who accept the general doctrine of Evolution, it need scarcely be pointed out that classifications are subjective conceptions, which have no absolute demarcations in Nature corresponding to them. ”

“ It is true, moreover, that while, in virtue of their heterogeneity, the actions going on in a cloud, in a volcano, in a glacier, fulfil the definition; they fall short of it in lacking definiteness of combination. It is further true that this definiteness of combination distinguishes the changes taking place in an organism during life from those which commence at death. ”

“ It is true that in some inferior creatures the cycle of successive changes admits of a certain indefiniteness—that it may be suspended for a long period by desiccation or freezing, and may afterwards go on as though there had been no breach in its continuity. ”

“ The last fact which this statement brings into view—the persistence of a living organism as a whole, in spite of the continuous removal and replacement of its parts—is important. But otherwise it may be argued that, since changes of structure and composition, though concomitants of muscular and nervous actions, are not the muscular and nervous actions themselves, the definite excludes the more visible movements with which our idea of life is most associated ”

“ They alter in nature with the temperature. If the local conditions are unlike, they progress differently in different parts of the mass, without mutual influence. They may end in producing gases, or adipocire, or the dry substance of which mummies consist. They may occupy a few days or thousands of years. Thus, neither in their simultaneous nor in their successive changes, do dead bodies display that definiteness of combination which characterizes living ones. ”