“Both the scientific and the everyday elbow are one and the same system of electrical charges. It is of no use asking physics and chemistry whether it is alive. They do not understand the word.”

— Charles Sherrington (1938), Man on His Nature (pg. 236)

“When physics and chemistry have entered on their description of the perceptible, life disappears from the scene, and consequently death. Both are anthropisms.”

— Charles Sherrington (1938), Man on His Nature (pg. 260)

See also: Animal heat; Combustion theory of animal heat; Vital heat

Sherrington uses the work and theories of French physician-philosopher Jean Fernel (1497-1558) as a springboard for many of the topics discussed in Man and His Nature.

“If there is one attribute which more widely than any other is evident as inherent in life it is warmth. In that we come across a great thing. A great thing like those great things which were found by the ancients. It is the innate heat. A law common to all animal kind, an ordinance of nature, is that they live by innate heat. While they live they are possessed of heat appropriate to them. When dead that heat is extinguished and they are cold. That is plain even to sense; it is heat sensible to man; a touch demonstrates it. It is however not so evident in plants. Yet in them no less than in animals it holds true. Further, the more sentient and active the animal the greater and more liberal the heat it has. If you as a reason, think on the excellence of the sun, prime prince and controller of the world, favoring and forwarding every life that is. By its chastened heat it supports them from without in doing what life does. Now if its heat from without can so cherish, whereas cold checks, life, is there not within living things a heat which cherishes what they do, a heat which even of the same nature as the suns? Did not Aristotle well and truly say, and leave it written for all posterity, that: ‘Heat is the condition of life’?

He defined death as the extinction of heat. Now this heat is innate heat. The innate heat is a heat which can be observed to survive even in the coldness of the decrepitude of age. The coldness of old age dominates, it is true, the material fire which is in the temperament, by the old age cannot, so long as there is life, overcome the innate heat itself. It is in the virtue of this heat that the snake lives, although its temperament is cold. So too mandragora, and the poppy and all of the herbs of the frigid temperament.

Whence it is clear that innate heat is superior to elemental heat. Elemental cold avails against elemental heat, but it avails nothing against this more excellent heat which is the innate heat of living things. Therefore this innate heat is not of the same nature as fire. It comes from a source superior to fire. In defining death, Aristotle, with the intuition of a master, said that: ‘Coldness of death comes not by mere overthrow of the temperament—not by surcharge of elemental cold, but by lapse of innate heat. Innate heat, vital heat, like light has no opposite. Light had not ‘contrary’; darkness is but privation of light. Death is a privation of innate heat, vital heat.’

This heat is not of the commingling of the elements. The body at death demonstrates that. Death occurs and still the body retains the structure and shape in all its parts. We recognize our friend, although his life is not there, and his heat is not there. The innate heat has fled him. It is not therefore traceable to the elements. They still compose the body. Therefore the innate heat—the vital heat—must have its source ‘elsewhere’.”

“The stone selenite holds the image of the moon even to her very phases. The magnet-stone points to the pole star. These are dead things, says Brutus, do living things likewise draw influences from the sky.”

“Deep down among human intuitions is one that spontaneous movement means life. Our kith and kin among the animals entertain it as well as we, though for them ‘life’ is, of course, an unconceptualized thought. We know from ourselves that the indirect field of sight will see what moves when it fails to see what does not move. Our horse may shy at a blown leaf on the roadway, not at a still one. The frog snaps at a fly that moves, but not at one which is still. The vine-tendril never lives so vividly as when at the cinema its clasping s speeded into visible movement. When the cardboard puppet dances it becomes thinkably alive, and Don Quixote’s irruption at the puppet-theater becomes intelligible. The biologist knows this intuitive inference as native, even to a primitive mind.

Movement accepted as spontaneous implies living. And the motion of the planets seemed to be spontaneous. Their movement told men that they were alive. All stars might be alive, but of them all the planets most so. The other stars were ‘fixed’, that is, relatively to each other did not move.”

See main: Defunct theory of life

“Aristotle noted of life that its lower limit defies demarcation. The living and non-living, he thought, merge one in the other gradually. Today the very distinction between them is convention. That deletes ‘life’ as a scientific category; or, if you will, carries it down to embrace the atom. The vanishing point of life is lost.”

“To ask the definition of life is to ask a something on which proverbially no satisfactory agreement obtains.”

“A speck of material which is said to ‘live’, while the vast majority of specks of material are said to be lifeless? Has it some particular element of matter in it which those other specks have not? No; that is not the key. The elements of matter—and we are thinking of them now not in Fernel’s sense [four elements] but in that stricter one of the chemistry of today—in the living cell are among the very commonest of those spread broadcast in material which does not ‘live’, in soil, rock, air and water. Perhaps what strikes us most in the list of chemical elements which make up us, is the negative fact that the majority of elements are left out, and all the rarer ones. But in the speck that lives the common elements are differently compounded.”

“Chemistry [does] not know the word life.”

A 2013 image of a T4 virus, which reproduces or infects its host (bacteria cells) via stinger-like injection of its DNA, a molecular structure that, as Sherrington says, we "hesitate whether or not to call it ‘living’."

“Life is an example of the way in which an energy-system in its give and take with the energy-system around it can continue to maintain itself for a period as a self-centered, so to say, self-balanced unity.”

“Perhaps the most striking feature of it is that it acts as though it ‘desired’ to maintain itself. But we do not say of the spinning of a heavy top which resists being upset that it ‘desires’ to go on spinning. The very constitution of the living system may compel it to increase; thus a self-fermenting protein system, granted its conditions, must increase. The behavior of a living body is an example of this, and we call it ‘living’. The behavior of the atom is an example of this and we do not call it ‘living’. The behavior of those newly discovered so-called ‘viruses’ is an example of this and there is hesitation whether or not to call it ‘living’.”

“The difference is one not of ultimate nature but of scheme and degree of complexity. The atoms and sub-atoms are among earth’s commonest. ‘Living’ becomes a name for certain complexes of them, arrangements of which it may be said that they are organized integratively, i.e. to form a solidarity, and individual.”

“These ‘faculties’, as Fernel has described, of moving, of ingesting, of excreting and secreting, are processes which examination resolves wholly into chemistry and physics. Chemistry and physics finds them not separable from the rest of chemistry and physics. What we call by convention ‘life’ is then chemical-physical. There is indeed no good ground for speaking of these as living, those as not-living.”

“When Professor Blackett speaks of the mean life of the mesotron particle and the Insurance Office speaks of the mean life of ourselves his particle’s behavior gives him no less right to do so than does ours the Insurance Office.”

“If a definition has to exclude as well as to include, it mist lean on a logical boundary of what it defines; the term life has no such boundary.”

Sherrington brings up the age-old "rock vs. human" comparison, as discussed adjacent, in order to prove his point, namely that: "to make ‘life’ a distinction between them is at root to treat them both artificially."

“The ‘motion’ of an energy system is its ‘behavior’. Various types of organization of system produce on that basis various types of behavior. A gray rock, said Ruskin, is a good sitter. That is one type of behavior. A darting dragon-fly is another type of behavior. We call the one alive, the other not. But both are fundamentally balances of give and take of motion with their surround. To make ‘life’ a distinction between them is at root to treat them both artificially.”

“Perhaps it would be a matter of discussion whether to call the earliest ‘living’ systems alive or not.”

“The animate and the inanimate as we have seen are in their ultimate parts alike, and fundamentally so in the principle of their construction. When we systematize, the animate falls unconstrainedly into series with the inanimate. The animate then becomes merely a special case within the more general. Analogously, the chemistry of the whole series of the carbon compounds taken within the chemical system is merely a special case within the more general.”

See main: Unbridgeable gap

“Now such a transition from lifeless to living is thinkable if it be at root an affair of chemical rearrangement. But as transition from one fundamental category of things to another fundamentally different one is unthinkable. The living and the lifeless studied as energy present no difference that rearrangements of their parts will not account for.”

“Perhaps we had left that mysterious transition from non-living to living as too akin to the miraculous to be understandable by as a process. That mysterious passage from ‘lifeless’ to ‘living’—to ‘life’, the indefinable, the inexplicable! Life, we know, can be fed with matter but for us to comprehend that matter’s becoming ‘alive’ to trace it ‘en passage’ from one category of nature to another? What question is there we can put to it about its change as it passes across the boundary from ‘dead’ to ‘alive’? Yes; but suppose, Cleanthes, that boundary to be a figment? The passage then too becomes imaginary. The difficulty becomes an imaginary one. Chemical partial repatterning might then be all, and quite intelligible to the chemist.”

“In the middle ages, and after them with Fernel, as with Aristotle before, there was the difficulty of the animate and the inanimate and finding of the boundary between them. Today’s scheme makes plain why that difficulty was, and dissolves it. There is no boundary.”

“But if there be no essential difference between ‘life’ and all the rest, what becomes of the difference between mind and no-mind.”

“To answer we may follow this hierarchy of systems and things downward and see at what point mind quits. Unless we can do that who knows that mind has left it? Of ourselves, yes we know we have a mind. And the dragon-fly? Yes, it may have a mind. And, amoeba? It may have, but how are we to know? Then of the grey rock?”

“Security of our inference regarding mind fades as traced downwards along the scale of being. Ultimately mind so traced seems to fade to no mind. It becomes so meager that the problem becomes that of trying to prove a negative.”

“The word ‘life’ still remains useful; a convenient, though not exact term.”

The Charles Sherrington commemorative stained glass window (1990), in the dining hall of Gonville and Caius College, Cambridge, depicting one of his own diagrams showing an afferent neuron or specifically: “two excitatory afferents with their field of supraliminal effect in the motoneurone pool of a muscle”, which might give a loose idea of his notion of an "organized complex" or tentatively “life” (a term which he puts to scrutiny), being but an “eddy in a stream of energy”, a stream “destined by the second law of thermodynamics.” [4]

“The living energy-system, in commerce with its surround, tends to increase itself. If we think of it as an eddy in the stream of energy it is an eddy which tends to grow; as part of this growth we have to reckon with its starting other eddies from its own resembling its own. This propensity it is which furnishes opportunity under the factors of evolution for a continual production of modified patterns of eddy. It is as though they progress toward something. But philosophy reflects that the motion for the eddy is in all cases drawn from the stream, and the stream is destined, so the second law of thermodynamics says, irrevocably to cease. The head driving it will, in accordance with the ascertained law of dynamics, run down. A state of static equilibrium will then replace the stream. And yet they will have been evolved. There purpose then was temporary? It would seem so.”

“For me now the only reality is the human soul.”

— Charles Sherrington (1952), statement made to John Eccles, during “deeply moving discourse”, nine days before his death (reaction end), Feb 24 [10]

“Sherrington’s Integrative Action of the Nervous Systems (1904) in neurology holds a position similar to that of Newton’s Principia in physics. Here is the imprint of a scientific genius.”

— FMR Walsh (c.1920) (Ѻ)

“Natural science has studied life to the extent of explaining away life as any radically separate category of phenomena. The categories of living and lifeless as regards science disappear; there is no radical scientific difference between living and dead. Time was when to think and to breathe were on an equality as attributes of life. Now, living, so far as breathing, moving, assimilating, growing, reproducing, etc. amount to life, has by natural science been accounted for—some might say, ‘explained’. There is nothing in them which does not fall within the province of science. There are chemistry and physics.”

— Charles Sherrington (c.1938)

“The self is a unity. The continuity of its presence in time, sometimes hardly broken by sleep, its inalienable "interiority" in (sensual) space, its consistency of view-point, the privacy of its experience, combine to give it status as a unique existence. . . . It regards itself as one, others treat it as one. It is addressed as one, by a name to which it answers. The law and the state schedule it as one. It and they identify it with a body which is considered by it and them to belong to it integrally. In short, unchallenged and unargued conviction assumes it to be one. The logic of grammar endorses this by a pronoun in the singular. All its diversity is merged into oneness.”

— Charles Sherrington (1947), “Preface” to The Integrative Action of the Nervous System [11]