(A partir d’unes conferències a Dublin el 1943. Encara no s’havia establert l’estructura i paper del DNA).
The large and important and very much discussed question is:
How can the events in space and time which take place within the spatial boundary of a living organism be accounted for by physics and chemistry?
The preliminary answer which this little book will endeavour to expound and establish can be summarized as follows:
The obvious inability of present-day physics and chemistry to account for such events is no reason at all for doubting that they can be accounted for by those sciences.
- Un cristall aperiòdic
The most essential part of a living cell the chromosome fibre may suitably be called an aperiodic crystal. In physics we have dealt hitherto only with periodic crystals. To a humble physicist’s mind, these are very interesting and complicated objects; they constitute one of the most fascinating and complex material structures by which inanimate nature puzzles his wits. Yet, compared with the aperiodic crystal, they are rather plain and dull. The difference in structure is of the same kind as that between an ordinary wallpaper in which the same pattern is repeated again and again in regular periodicity and a masterpiece of embroidery, say a Raphael tapestry, which shows no dull repetition, but an elaborate, coherent, meaningful design traced by the great master. [Ignorant això, a Layered Ontology jo apuntava que la Física és la ciència dels sistemes uniformes, gasos, líquids, sòlids, res a veure amb la complexitat de la vida]. - Aleatori individual, predictible en grans números
Per què han de ser tant petits els àtoms i tan grossos els nostres cossos? (Suppose that you could mark the molecules in a glass of water; then pour the contents of the glass into the ocean and stir the latter thoroughly so as to distribute the marked molecules uniformly throughout the seven seas; if then you took a glass of water anywhere out of the ocean, you would find in it about a hundred of your marked molecules.) [Els àtoms estan vibrant i sotmesos a la incertesa, ab comportaments impredictibles. Només quan en tenim molts i podem tenir comportaments promigs que ens dóna la mecànica estadística. El moviment Brownià mostra les vibracions dels àtoms, l’agitació tèrmica. La inexactitud d’una llei quant al nombre de partícules n és de l’ordre de 1/√n. [Per tenir un comportament ordenat, doncs i protegit dels moviments monoatòmics aleatoris, un organisme viu ha de ser un sistema de moltes partícules. - El mecanisme de l’herència
[Com aconseguim mantenir i transmetre un ordre?] In calling the structure of the chromosome fibres a code-script we mean that the all-penetrating mind, once conceived by Laplace, to which every causal connection lay immediately open, could tell from their structure whether the egg would develop, under suitable conditions, into a black cock or into a speckled hen, into a fly or a maize plant, a rhododendron, a beetle, a mouse or a woman.
The egg divides into two ‘daughter cells’ which, at the next step, will produce a generation of four, then of 8, 16, 32, 64, . . ., etc. The frequency of division will not remain exactly the same in all parts of the growing body, and that will break the regularity of these numbers. But from their rapid increase we infer by an easy computation that on the average as few as 50 or 60 successive divisions suffice to produce the number of cells2 in a grown man or, say, ten times the number,2 taking into account the exchange of cells during lifetime. Thus, a body cell of mine is, on the average, only the 50th or 60th ‘descendant’ of the egg that was I.
[Podem estimar que un gen és de l’ordre d’uns 300 Angstroms, tot just 100 distàncies atòmiques. Els raigs X augmenten les mutacions]. - Com expliquem que es mantingui l’ordre dels gens?
How can we, from the point of view of statistical physics, reconcile the facts that the gene structure seems to involve only a comparatively small number of atoms (of the order of 1,000 and possibly much less), and that nevertheless it displays a most regular and lawful activity with a durability or permanence that borders upon the miraculous? El gen es conserva a 36.6º!
- Energia quantificada
Les pertorbacions no tenen efecte perquè l’energia està quantificada i cal aportar un mínim per canviar d’estat. El temps esperat depèn de la temperatura segons τeW/kt. We believe a gene or perhaps the whole chromosome fibre to be an aperiodic solid. - Ordre, desordre i entropia
Life seems to be orderly and lawful behaviour of matter, not based exclusively on its tendency to go over from order to disorder, but based partly on existing order that is kept up.
To the physicist but only to him I could hope to make my view clearer by saying: The living organism seems to be a macroscopic system which in part of its behaviour approaches to that purely mechanical (as contrasted with thermodynamical) conduct to which all systems tend, as the temperature approaches the absolute zero and the molecular disorder is removed./ Living Matter Evades the Decay to Equilibrium / When a system that is not alive is isolated or placed in a uniform environment, all motion usually comes to a standstill very soon as a result of various kinds of friction; differences of electric or chemical potential are equalized, substances which tend to form a chemical compound do so, temperature becomes uniform by heat conduction. After that the whole system fades away into a dead, inert lump of matter. A permanent state is reached, in which no observable events occur. The physicist calls this the state of thermodynamical equilibrium, or of ‘maximum entropy’. / It Feeds on ‘Negative Entropy’. How does the living organism avoid decay? The obvious answer is: By eating, drinking, breathing and (in the case of plants) assimilating. The technical term is metabolism. Thus a living organism continually increases its entropy or, as you may say, produces positive entropy and thus tends to approach the dangerous state of maximum entropy, which is death. It can only keep aloof from it, i.e. alive, by continually drawing from its environment negative entropy which is something very positive as we shall immediately see. L’entropia és una mesura del desordre [uniformitat tèrmica] Entropia = k log (Desordre). - Is Life Based on the Laws of Physics?
The unfolding of events in the life cycle of an organism exhibits an admirable regularity and orderliness, unrivalled by anything we meet with in inanimate matter. We find it controlled by a supremely well-ordered group of atoms, which represent only a very small fraction of the sum total in every cell. Moreover, from the view we have formed of the mechanism of mutation we conclude that the dislocation of just a few atoms within the group of ‘governing atoms’ of the germ cell suffices to bring about a well-defined change in the large-scale hereditary characteristics of the organism.An organism’s astonishing gift of concentrating a ‘stream of order’ on itself and thus escaping the decay into atomic chaos of ‘drinking orderliness’ from a suitable environment seems to be connected with the presence of the ‘aperiodic solids’, the chromosome molecules, which doubtless represent the highest degree of well-ordered atomic association we know of much higher than the ordinary periodic crystal in virtue of the individual role every atom and every radical is playing here.
Els sistemes físics: Even when the chemist handles a very complicated molecule in vitro he is always faced with an enormous number of like molecules. To them his laws apply. He might tell you, for example, that one minute after he has started some particular reaction half of the molecules will have reacted, and after a second minute three-quarters of them will have done so. But whether any particular molecule, supposing you could follow its course, will be among those which have reacted or among those which are still untouched, he could not predict. That is a matter of pure chance.
Els sistemes biològics: In biology we are faced with an entirely different situation. A single group of atoms existing only in one copy produces orderly events, marvellously tuned in with each other and with the environment according to most subtle laws…. Every cell harbours just one of them (or two, if we bear in mind diploidy). Since we know the power this tiny central office has in the isolated cell, do they not resemble stations of local government dispersed through the body, communicating with each other with great ease, thanks to the code that is common to all of them? - Si tot és física, no hi ha lliure albir?
To the physicist I wish to emphasize that in my opinion, and contrary to the opinion upheld in some quarters, quantum indeterminacy plays no biologically relevant role in them, except perhaps by enhancing their purely accidental character in such events as meiosis, natural and X-ray-induced mutation and so on and this is in any case obvious and well recognized.
i) My body functions as a pure mechanism according to the Laws of Nature.(ii) Yet I know, by incontrovertible direct experience, that I am directing its motions, of which I foresee the effects, that may be fateful and all-important, in which case I feel and take full responsibility for them.[S apunta en la direcció dels místics que se senten connectats amb tot, the mystics of many centuries, independently, yet in perfect harmony with each other (somewhat like the particles in an ideal gas) have described, each of them, the unique experience of his or her life in terms that can be condensed in the phrase: DEUS FACTUS SUM (I have become God).
Però també: Consciousness is never experienced in the plural, only in the singular. ..How does the idea of plurality (so emphatically opposed by the Upanishad writers) arise at all? Consciousness finds itself intimately connected with, and dependent on, the physical state of a limited region of matter, the body. [la negreta és meva. No tot està connectat, en un experiment sobre situacions en les quals jo deicideixo, els factors que influeixen són la meva identitat, la meva manera de ser, ls meves expectatives. Certament amb una base biològica i neurològica, però una part de l’univers que és el que anomenem “jo” o “self”.]
The only possible alternative is simply to keep to the immediate experience that consciousness is a singular of which the plural is unknown; that there is only one thing and that what seems to be a plurality is merely a series of different aspects of this one thing, produced by a deception (the Indian MAJA); the same illusion is produced in a gallery of mirrors, and in the same way Gaurisankar and Mt Everest turned out to be the same peak seen from different valleys. [S suggeriria que el jo és il·lusori]Yet each of us has the indisputable impression that the sum total of his own experience and memory forms a unit, quite distinct from that of any other person. He refers to it as ‘I’. What is this ‘I’? If you analyse it closely you will, I think, find that it is just a little bit more than a collection of single data (experiences and memories), namely the canvas upon which they are collected. And you will, on close introspection, find that what you really mean by ‘I’ is that ground-stuff upon which they are collected. You may come to a distant country, lose sight of all your friends, may all but forget them; you acquire new friends, you share life with them as intensely as you ever did with your old ones. Less and less important will become the fact that, while living your new life, you still recollect the old one. ‘The youth that was I’, you may come to speak of him in the third person, indeed the protagonist of the novel you are reading is probably nearer to your heart, certainly more intensely alive and better known to you. Yet there has been no intermediate break, no death. And even if a skilled hypnotist succeeded in blotting out entirely all your earlier reminiscences, you would not find that he had killed you. In no case is there a loss of personal existence to deplore. [el jo és fràgil i canviant, però és l’experiència més important qie tenim, i menystenir-lo com a il·lusori és pobre. Amb una antropologia determinista un dimoni de Laplace veure com es va fent i desfent aquest conjunt de records i d’expectatives i com a cada moment decideix. Determinisme subspecie aeternitatis i experiència de llibertat. I resulta que el nostre punt de vista, allà on estem en l’experiment, és dins la capsa, no fora sub specie aeternitatis]