What is life Schrödinger pdf download. What is life from a physics point of view? General nature and purpose of the study

What is life?

Lectures given at Trinity College, Dublin in February 1943.

Moscow: State Publishing House of Foreign Literature, 1947 - p.150

Erwin Schrödinger

Professor at the Dublin Research Institute

WHAT IS LIFE

from a physics point of view?

WHAT IS LIFE?

The Physical Aspect of the

Living Cell

BRWIN SGHRODINGER

Senior Professor at the Dublin Institute for Advanced Studies

Translation from English and afterword by A. A. MALINOVSKY

Artist G. Riftin

Introduction

Homo liber nulla de re minus quam

de morte cogitat; et ejus sapientia

non mortis sed vitae meditatio est.

Spinoza, Ethica, P. IV, Prop. 67.

A free man is nothing like that

little does not think about death, and

his wisdom lies in reflection

not about death, but about life.

Spinoza, Ethics, Part IV, Theor. 67.

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Preface

It is generally believed that a scientist must have a thorough first-hand knowledge of a particular field of science, and it is therefore believed that he should not write on such matters in which he is not an expert. This is seen as a matter of noblesse oblige. However, in order to achieve my goal, I want to renounce noblesse and ask, in this regard, to release me from the obligations arising from it. My apologies are as follows.

We have inherited from our ancestors a keen desire for unified, all-encompassing knowledge. The very name given to the highest institutions of knowledge - universities - reminds us that from ancient times and for many centuries the universal nature of knowledge was the only thing in which there could be complete trust. But the expansion and deepening of various branches of knowledge during the last hundred wonderful years has presented us with a strange dilemma. We clearly feel that we are only now beginning to acquire reliable material in order to unite into one whole everything that we know; but on the other hand, it becomes almost impossible for one mind to completely master more than any one small specialized part of science.

I see no way out of this situation (without our main goal being lost forever) unless some of us venture to undertake a synthesis of facts and theories, even though our knowledge in some of these areas is incomplete and obtained at second hand and at least we ran the risk of appearing ignorant.

Let this serve as my apology.

Difficulties with language are also of great importance. Everyone’s native language is like a well-fitting garment, and you cannot feel completely free when your language cannot be at ease and when it must be replaced by another, new one. I am very grateful to Dr Inkster (Trinity College, Dublin), Dr Padraig Brown (St Patrick's College, Maynooth) and last but not least, Mr S. C. Roberts. They had a lot of trouble trying to fit me into new clothes, and this was aggravated by the fact that sometimes I did not want to give up my somewhat “original” personal style. If any of it survives despite the efforts of my friends to soften it, it must be attributed to me, and not to theirs.

Initially, it was assumed that the subheadings of numerous sections would have the nature of summary inscriptions in the margins, and the text of each chapter should be read in continue (continuously).

I am greatly indebted to Dr. Darlington and the publisher Endeavor for the illustration plates. They retain all the original details, although not all of these details are relevant to the content of the book.

Dublin, September, 1944. E. Sh.

A classical physicist's approach to the subject

Cogito, ergo sum

Descartes.

General nature and objectives of the study

This small book arose from a course of public lectures given by a theoretical physicist to an audience of about 400 people. The audience almost did not decrease, although from the very beginning it was warned that the subject of presentation was difficult and that the lectures could not be considered popular, despite the fact that the most terrible tool of a physicist - mathematical deduction - could hardly be used here. And not because the subject is so simple that it can be explained without mathematics, but rather the opposite - because it is too complicated and not entirely accessible to mathematics. Another feature that gave at least the appearance of popularity was the intention of the lecturer to make the main idea associated with both biology and physics clear to both physicists and biologists.

Indeed, despite the variety of topics included in the book, as a whole it should convey only one idea, only one small explanation of a large and important issue. In order not to deviate from our path, it will be useful to briefly outline our plan in advance.

The big, important and very often discussed question is this: how can physics and chemistry explain those phenomena in space and time that take place inside a living organism?

The preliminary answer that this little book will try to give and develop can be summed up as follows: the obvious inability of modern physics and chemistry to explain such phenomena gives absolutely no reason to doubt that they can be explained by these sciences.

Statistical physics. The main difference is in the structure

The foregoing remark would be very trivial if it were intended only to stimulate the hope of achieving in the future what was not achieved in the past. It, however, has a much more positive meaning, namely, that the inability of physics and chemistry to date to provide an answer is completely understandable.

Thanks to the skillful work of biologists, mainly geneticists, over the last 30 or 40 years, enough has now been known about the actual material structure of organisms and their functions to understand why modern physics and chemistry could not explain the phenomena in space and time that occur within living things. body.

The arrangement and interaction of atoms in the most important parts of the body are radically different from all those arrangements of atoms with which physicists and chemists have hitherto dealt in their experimental and theoretical research. However, this difference, which I just called fundamental, is of a kind that can easily seem insignificant to anyone except a physicist, imbued with the idea that the laws of physics and chemistry are thoroughly statistical. It is from a statistical point of view that the structure of the most important parts of a living organism is completely different from any piece of matter with which we, physicists and chemists, have hitherto dealt, practically - in our laboratories and theoretically - at our desks. Of course, it is difficult to imagine that the laws and rules that we have discovered would be directly applicable to the behavior of systems that do not have the structures on which these laws and rules are based.

Erwin Schrödinger's book "What is life from the point of view of physics?" It was first published in England during the war in 1944, after which it went through several editions without changes and caused lively responses in the foreign scientific and general press. One enthusiastic reviewer even expressed the opinion that it created an entire era in science, and compared it in this regard with such works as the work of the pioneer of statistical thermodynamics, Willard Gibbs, and the founder of scientific genetics, Gregor Mendel.

It is difficult to agree with such a high assessment of the book, and there is no doubt that it was partly caused by both the somewhat sensational title of the book and the wide popularity of the author - one of the greatest scientists of our time. To make it clear to readers who are not specialists in the field of modern physics who the author of this book is, we point out that, listing the creations equivalent to Isaac Newton’s Principia, Academician S. I. Vavilov, along with the theory of atoms and electrons and the theory of relativity A Einstein also points to quantum (wave) mechanics, the creator of which was Schrödinger. In recognition of his outstanding works, E. Schrödinger was elected in 1934 as an honorary member of the USSR Academy of Sciences.

The question posed in the title - “What is life?”, as well as the philosophical epilogue - “On determinism and free will” - also could not help but attract the attention of scientific and general readership circles.

However, Schrödinger's book is of great importance on its merits. What is its value?

Schrödinger, in his book, in a form that is fascinating and accessible to both physicists and biologists, reveals to the reader a new, rapidly developing direction in science, which largely combines the methods of physics and biology, but which was until now accessible only to a very narrow circle of people, having special literature.

In our time, ever deeper penetration into the structure of a living cell has required the use of a number of methods and concepts of modern physics. This gave rise to “real” biophysics, similar to the earlier biochemistry, which has already made a great contribution to the development of our knowledge about life. On the contrary, the use of physical methods (primarily optical, x-ray, etc.) has so far played an almost exclusively auxiliary role, helping only to discover certain biological facts without corresponding physical and general biological interpretation of them. It was physics for biology, but not physics in biology. In this respect, biophysics in its significant part was deeply different from biochemistry, which was not limited to the introduction of new methods, but long ago moved on to analyzing the essence of the most intimate chemical transformations occurring inside the body. Biophysics achieved such deepening into the essence of life phenomena only to a small extent (for example, in the study of electrophysiological processes, mitogenetic radiation, etc.), due to which it for the most part retained the position of an auxiliary science, although it contributed to the discovery of certain patterns, but not playing a completely independent role in the knowledge of life phenomena.

And only in our days has physics entered the field of biology with the goal of revealing those lower levels in the organization of living matter, the understanding of which is a necessary prerequisite for the future, a more complete and profound understanding of life in general.

Schrödinger's book represents, strictly speaking, the first coherent results of this direction, to which many more amendments will undoubtedly be made, but which basically outline certain outlines of the new scientific edifice of “real” biophysics.

If Schrödinger's book were limited to just the presentation of what was given, then this would be enough to recognize its significance. But Schrödinger makes a great personal contribution to this new direction of life science, which largely justifies the enthusiastic reviews that his book received in the foreign scientific press.

Along with many more specific considerations, Schrödinger puts forward an extremely broad and fruitful thought. He outlines the connection between two biological “mysteries,” namely: the question of the nature of hereditary structures and the seemingly so distant question of the relationship of organisms to the second law of thermodynamics. The latter, although not “cancelled” for living beings, is to a large extent “managed” by them. Schrödinger shows that the most important condition for this (if not the reason) is the special specific structure of the central apparatus of the cell - the chromosomes. Chromosomes, by their structure, are capable, as a “mechanical” (as opposed to “thermodynamic”) system of extraordinary complexity, to directly support the regular course of many biological processes, ensuring the minimum size of the “regulatory apparatus” of the cell.

All this makes Schrödinger’s book very valuable, despite its significant shortcomings, which we will discuss below. It was this positive side of Schrödinger’s small book that attracted the attention of a number of major scientists - Holden, Meller and Delbrück, who devoted large reviews to it. It will be useful to briefly introduce the reader to these reviews.

In his review of Schrödinger's book, the largest English biologist and progressive public figure, Prof. J. B. S. Hallden gives her very high marks; at the same time, he makes a number of critical remarks. First of all, he rightly notes that Schrödinger’s view of the chromosome as a giant molecule (Schrödinger’s “aperiodic crystal”) was first put forward by the Soviet biologist Prof. N.K. Koltsov, and not Delbrück, with whose name Schrödinger associates this concept.

Moving to the essence of the issue, Holden believes that if we consider a gene as a molecule with the property of a catalyst, then, contrary to Schrödinger’s opinion, the principles of statistical mechanics are quite applicable even to a single gene. A single catalyst molecule can, under favorable conditions, convert more than 100 thousand substrate molecules per second, and these are figures that fully allow for a statistical approach to research. In general, Holden believes that although Delbrück's ideas correspond very fully to the known facts, they, as has been repeatedly observed in quantum mechanics, must change greatly. He refers to unpublished work by Lee and Cotcheside (presented to the English Genetics Society) in which the authors find that most of the lethal mutations caused by irradiation of Drosophila sperm are the result of chromosome breakage followed by their repair, and, for example in Tradescaniia, such a breakage requires about 17 ionization onto the chromatid. On the other hand, Fabergé and Beale discovered that the high mutation rate of one very unstable gene was markedly reduced at high temperatures. “It is possible,” Holden concludes, “that more complex phenomena occur in chromosomes than can be imagined even on the basis of the principles of wave mechanics.”

Noting that Schrödinger does not raise a number of biological problems at all, Holden points in particular to the problem of regulating disorders in the body, which some biologists find impossible to explain materialistically, and expresses the hope that Schrödinger will deal with these issues in the future.

Concluding the review with a serious criticism of Schrödinger's philosophical statements (which we will discuss below), Holden as a whole still gives a high assessment of the book, which, as he says at the beginning, every geneticist should read and which, by posing the question of the body's use of negative entropy, can enrich and physiologist

Similar thoughts about Schrödinger’s book are expressed by the famous American geneticist H. J. Moeller. In his opinion, to the very important features of living matter discussed in Schrödinger’s book, one should add another deeper and not touched upon by the author basic property of the gene - its ability to multiply and double. This ability underlies such fundamental biological phenomena as growth, reproduction and, finally, the evolution of living beings.

However, it would be a great simplification to consider this ability of the gene as simple autocatalysis, as Troland, for example, believed. The gene is capable of doubling and retains this ability even after mutation, that is, even having taken on a different form and exhibiting completely new properties in its influence on the development of the organism. This ability is not yet known for any autocatalyst. Any genes and their mutations can form an organic substrate into new genes similar to them. This is what provides the very possibility of evolution, through the accumulation and propagation of mutations experienced by genes. From this point of view, much less important for understanding the essence of life is the fact that mutations are precisely quantum leaps, because “organization” (“order” according to Schrödinger) in a specifically biological sense is primarily the result of the duplication of genes and selection. Biological "organization" is not at all so closely related to the accumulation of what biologists call potential energy (Schrodinger's "negative entropy").

The main observed trend in the development of living matter, according to Meller, is ensuring maximum safety and widespread distribution of its type of organization. This is often achieved in such qualitative ways that do not directly increase the “feeding of negative entropy”, but subsequently create enormous opportunities for utilizing external energy. This is, for example, the development of intelligence in a physically weak creature. Here, controlling energy for the benefit of the system is more important than increasing the energy content of the system itself.

In general, Möller believes that, despite its incompleteness and some minor shortcomings, Schrödinger’s book is very valuable in that it helps to resolve some problems that interest any scientist in general.

According to Max Delbrück, expressed in his review, Schrödinger’s book does not solve the question posed in its title - “What is life?” Having asked the question how physics and chemistry can explain processes in a living organism that occur in space and time, the author examines another, undoubtedly important, but much less significant question - whether physics and chemistry can explain the phenomena occurring in the body. Nevertheless, this book represents a focal point where the interests of physicists and biologists converge.

“To readers who are not familiar with Bohr’s special statements,” says Delbrück, “it may seem that the physical nature of the processes inside a living cell goes without saying, and it is difficult for them to appreciate the significance of the task facing the “naive physicist” at the beginning of the book. Delbrück believes that Schrödinger's discussion of the types of laws of nature ("statistical" and "dynamic") can have a "clarifying influence on biological thinking."

Summarizing the above reviews, it should be said that all reviews emphasize the great importance of Schrödinger’s book. Indeed, this book, as already mentioned, develops a new and extremely important direction in science, combining physics and biology and having broad prospects in the future. This attempt to synthesize physics and biology in solving the basic problem of life is all the more interesting because it is colored by the original, albeit inevitably subjective, ideas of such a major modern scientist as Schrödinger. The question of the relationship of living organisms to the principle of entropy received new coverage in Schrödinger's book, which is likely to give further impetus to the discussion of this issue. This is evidenced, for example, by Butler’s recent work on the experimental study of the second law of thermodynamics as applied to living organisms.

Schrödinger, with his generalizing attempt, took a big step towards introducing into everyday life biology those precise theoretical methods that have long been characteristic of physics, but (except for statistical methods of processing material) only occasionally and for the most part only in special works make their way into the science of life. It should be especially emphasized that, despite all his mechanistic methodology, Schrödinger - and this is the undoubted value of his book - comes, as a central idea, to the dialectical idea of ​​​​the specific, qualitative difference between living and nonliving things, although he limits this specificity only to the limits of physical organization alive.

Undoubtedly, the title of the book promises more than the author can deliver. The problem of life as a whole is immeasurably wider and deeper than the problems raised by Schrödinger in his book. Schrödinger considers only some of the basic questions of the organization of a living cell, but by no means the entire problem of life in all its complexity. However, he develops our ideas about the essence of life more deeply, and if formally the book does not give what is promised in the title, nevertheless, in essence, the claims that critics have made against it, demanding that the author explain such phenomena as gene duplication, can hardly be justified , regulation of physiological processes, etc. Here it is appropriate to recall the words of K. A. Timiryazev, where he credits Pasteur with the fact that he was able to raise the question that was next in line in science, and resolved this particular one, and not any other , an equally important question, which, however, can only be resolved at the next stage of the study, in particular, after a preliminary study of the first question.

We will not dwell here on individual remarks, although some of them (such as Holden's remark about the possibility of a statistical approach to a single gene) were apparently generated by some kind of misunderstanding. It is much more interesting to consider the philosophical and, in particular, epistemological views that Schrödinger expressed in the epilogue.

As a prominent scientist, Schrödinger took a clear materialist position in scientific research. He specifically emphasized that he not only does not think of any “supernatural”, non-physical forces in the body, but also does not try to disguise them in the physical clothing of “quantum indeterminism” (which some physicists, for example Jordan and others, are apparently inclined to do). Schrödinger's weakness appears even more clearly when he concerns general philosophical issues.

It is difficult to give a more illustrative example in the field of biology, which so brilliantly and vividly confirms the correctness of the famous statement: V. I. Lenin’s statement: “Not a single one of these professors, capable of giving the most valuable work in the special fields of chemistry, history, physics, can be trusted not in a single word, since we are talking about philosophy." (Lenin, Op. Vol. XIII, p. 280.)

And indeed, raising in his book the central problem of the question of the specificity of living matter, Schrödinger, not only in a specific scientific analysis, but also in the very formulation of the question, limits it exclusively to the level of primitive physical organization, which is partly what caused the criticism of his book by Holden and Möller. It seems that it was precisely this limitation of Schrödinger that F. Engels polemicized when he wrote: “We will undoubtedly “reduce” thinking someday experimentally to molecular and chemical movements in the brain, but does this exhaust the essence of thinking?” ("Dialectics of Nature.")

However, if in scientific research this methodological primitivism of Schrödinger was reflected only in a limited formulation of the question, then in his purely philosophical views he already acts as a direct idealist.

Discussing the “Delbrück model,” Schrödinger states that if it turned out to be untenable, then it would be necessary to completely stop further attempts to understand the essence of the processes occurring in a living cell. Holden, in his review, responds correctly by pointing to an example very close to Schrödinger, when it would seem that the later development of physics made significant changes to such a perfect picture of the atom, proposed by Bohr.

The current state of theoretical physics, as well as achievements in the field of studying the structure of matter, fully confirm Lenin’s insightful idea of ​​​​approaching knowledge to absolute truth through a series of relative truths and completely refute this statement of Schrödinger.

Schrödinger’s statement is also completely idealistic when he says that the “mystery” of psychophysical parallelism is insoluble for the human mind (§ 5), just as, in his opinion, the very ways of knowing the world cannot be understood by this mind (§ 19). Here the idealist Schrödinger appears as a typical agnostic.

But with exceptional nakedness this metaphysical gap between science and subjective philosophy of Schrödinger was reflected in his short epilogue “On Determinism and Free Will,” where in a few pages he tries to answer some basic questions of philosophy, borrowing their solution from the Hindu Upanishads, the philosophy of Schopenhauer and others mystical-idealistic philosophical systems. Schrödinger himself is aware of this gap between his philosophy and science. “As a reward for my labor in presenting the purely scientific side of our problem sine ira et studio, I now ask permission to express my own, inevitably subjective view of the philosophical significance of the question” (p. 121), he writes. The reason for this gap is that a major scientist who reveals the objective laws of nature, Schrödinger, in his methodological attitude to science remains an incorrigible idealist, and in his general mentality - a typical son of the social system and class to which he belongs. Schrödinger's philosophical idealism, which stems from his mechanistic method, is unable to provide correct answers to the philosophical questions he raises.

Schrödinger argues that one individual consciousness is, as such, inaccessible to another individual consciousness (p. 124). From this he concludes that consciousness is generally a single phenomenon and, therefore, the presence of “many consciousnesses” is an illusion. Such a conclusion naturally leads Schrödinger to the final conclusion of his entire idealistic philosophy about the unknowability of the world in general.

This old agnostic fable was brilliantly exposed long ago by Lenin precisely on the example of the physical sciences in his classic work “Materialism and Empirio-Criticism.” Holden also provides a witty objection to this basic position of Schrödinger. He says that a physicist has no way of distinguishing between the two electrons of a hydrogen molecule. They are just as devoid of individual traits as the “fact of consciousness.” Nevertheless, there are still two electrons, and not one. But what does not confuse Schrödinger in physics close to him becomes insoluble for him in the field of philosophy. For the same reason, other philosophical questions raised by him in the epilogue are equally insoluble for Schrödinger. He writes that "immediate perceptions, however different and incomparable they may be, cannot in themselves logically contradict each other. Let us therefore see whether we cannot arrive at a correct and consistent conclusion from the following two premises" (p. 122 ). What are these “preconditions” and what “immediate perceptions” that “cannot logically contradict each other” are we talking about?

In fact, direct perceptions cannot contradict each other: the sensation of pain in the hand - the sensation of bitterness on the tongue, or the image of a person on a movie screen - the sensation of a flat wall obtained by feeling the screen with the hand.

But Schrödinger contrasts not two direct perceptions with each other, but completely incomparable things. On the one hand, he takes the scientific conclusion made on the basis of countless facts and indicating that the human body in its functions is completely subject to the laws of nature, which he mechanistically formulates as follows: “My body functions as a pure mechanism...” (p. . 122). On the other hand, he exposes the subjective conviction that free will, human consciousness, dominates the material laws of the body. “However, from irrefutable (? Transl.) experience, I know that I control the actions of my body...” (ibid.). But if two perceptions cannot contradict each other, then the scientific explanation of a phenomenon very often contradicts a subjective belief based on untested, uncritically analyzed experience of everyday life. Thus, the optical explanation of the effects of cinema, of course, contradicts our immediate impression that really living people are moving on the screen.

But from this, of course, it does not follow that consciousness is independent of matter and “dominates” over it, as E. Schrödinger claims, who does not hide his direct philosophical bias and, arguing his positions, strives no more, no less than to “prove simultaneously the existence of God and the immortality of the soul" (p. 123).

It is more than obvious that in all this reasoning, Schrödinger makes an elementary logical error, erorr fundamentalis - a false fundamental position, as a result of which he proves not what needs to be proven, but something completely different, but outwardly similar. His syllogism is flawed, because he compares a scientifically substantiated conclusion arising from knowledge of objective laws with a subjective opinion devoid of any scientific significance.

That outwardly logical, but essentially vicious and helpless argumentation to which he resorts to prove the main thesis of his epilogue: “this means I am an omnipotent God” testifies to the deepest spiritual crisis in which modern bourgeois philosophy of science finds itself.

Schrödinger's complete philosophical obscurantism is obvious and beyond any doubt.

If it is true that the introduction to a book is often written after the main work, it is no less true that the conclusions are often outlined before the argument.

This happened to Schrödinger too. His conclusions reflect the ideology of a receding class-capitalist society, in which the relatively progressive mechanistic materialism of the era of early capitalism was replaced by various, increasingly reactionary forms of philosophy, up to various epistemological systems of an idealistic nature, like Schopenhauer and others. They have Schrödinger and borrows its general philosophical concepts. While remaining a major researcher in his special field, Schrödinger in the field of philosophy is content with philistine ideas, “a nonsense fable about free will” (Lenin, Soch., vol. I, p. 77). As a result, a kind of “crooked” logic arises, comparing scientific fact with subjective sensation, which leads him to the conclusion that he manages to “prove... the existence of God and the immortality of the soul.”

This is the main flaw in Schrödinger's entire logical argumentation, which, like a house of cards, falls apart at the slightest touch of dialectical criticism.

Schrödinger's philosophical speech received an extremely sharp rebuke in the aforementioned review by the leading American geneticist Möller, who regarded it as “old-fashioned mysticism” and pointed out that “biologists are shocked that they are witnessing these unreasonable brain exercises and fabrications on general issues of psychology and sociology.” He calls on biologists to respond to Schrödinger's philosophical speech by "flashing their red warning signal." “We must hope, however,” writes Möller, “that the unfortunate revelation of this physicist’s inner self will not prevent one from taking seriously the rather healthy exposition in the main part of the book and that an increasingly useful rapprochement between physics, chemistry and the genetic foundations of biology has finally become possible. on a solid path."

Undoubtedly, the reviewer is quite right here, and it would be very naive to try to connect these two so incompatible lines: Schrödinger the scientist and Schrödinger the philosopher. Just as in their time the spiritualistic “experiments” of Wallace and Crookes, which caused a well-deserved rebuke from Engels, did not in the least diminish the high appreciation of their purely scientific research, and Leibniz’s monadology did not hinder his great merits in the development of new mathematical thinking, so in this case subjective philosophical views a prominent physicist should not interfere with the correct assessment of the objective contribution he made to science.

The Soviet intelligentsia, brought up on the works of the classics of scientific communism, was ideologically mature enough to be critical of such a mixture of exact science and idealistic philosophy.

Following the precepts of V.I. Lenin, she is quite stable in relation to any idealistic fabrications, regardless of the fact that they are expressed by a major authority in a special field, she well understands the sources and causes of such a phenomenon and will therefore be able to differentiate the works of foreign scientists, assimilate and process the achievements that they have achieved in the study and comprehension of the real material world. She will be able to separate everything advanced and innovative that is in Schrödinger’s book from his ideological and philosophical obscurantism, which is so characteristic of many modern foreign scientists.

Living cell as a physical object

Based on lectures given in association with the Dublin Institute of Advanced Study at Trinity College, Dublin, February 1943.

In memory of my parents

As a young mathematics student in the early 1950s, I read little, but when I did, it was mostly by Erwin Schrödinger. I have always liked his work; there was a thrill of discovery in it, which promised a truly new understanding of the mysterious world in which we live. In this sense, the short classic work “What is Life?” especially stands out, which, as I now understand, should certainly be placed on a par with the most influential scientific works of the 20th century. It is a powerful attempt to understand the real mysteries of life - an attempt made by a physicist whose own insightful insights have greatly changed our understanding of what the world is made of. The book's multidisciplinary nature was unusual for its time, but it is written with an endearing, if disarming, modesty at a level accessible to non-specialists and young people aspiring to a scientific career. In fact, many of the scientists who made fundamental contributions to biology, such as B. S. Haldane and Francis Crick, acknowledged that they were significantly influenced by the various ideas, albeit controversial, put forward in this book by the thoughtful physicist.

Like many other works that influenced human thinking, What Is Life? presents points of view which, once internalized, appear to be almost self-evident truths. However, they are still ignored by many people who should understand what's what. How often do we hear that quantum effects are of little importance in biological research, or even that we eat food to get energy? These examples highlight the enduring significance of Schrödinger's What Is Life? Without a doubt, it is worth re-reading!

Roger Penrose

A scientist is expected to have complete and comprehensive first-hand knowledge of things and, therefore, should not write about something in which he is not an expert. As the saying goes, noblesse oblige. Now I ask you to forget about noblesse, if any, and be released from the corresponding obligations. My justification is this: from our forefathers we have inherited a strong desire for a single, all-encompassing knowledge. The very name of higher educational institutions reminds us that since ancient times and for many centuries the greatest attention has been paid to the aspect versatility. However, the growth - in breadth and depth - of various branches of knowledge over the last hundred or so years has forced us to face a strange dilemma. We clearly feel that we are just beginning to collect reliable material from which we can deduce the total sum of all known things. But on the other hand, now the individual mind can only master a small, specialized piece of knowledge.

I see only one way to deal with this dilemma (otherwise our true goal will be lost forever): someone must take upon himself the synthesis of facts and theories, even second-hand and incomplete, at the risk of making himself look like a fool.

That's my excuse.

Language difficulties should not be underestimated. The native language is like tailored clothing, and a person feels uncomfortable when he is deprived of access to it and is forced to use another language. I wish to express my gratitude to Dr Inkster (Trinity College, Dublin), Dr Patrick Brown (St Patrick's College, Maynooth) and, last but not least, Mr S. C. Roberts. It was not easy for them to fit new clothes to me and convince me to abandon the “original” turns. If some of them survived my friends' editing, it's my fault.

The section headings were originally intended to provide a summary, and the text of each chapter should be read in continuo.

Dublin

September 1944

The least free person thinks about death. In his wisdom, he reflects not on death, but on life.

Spinoza. Ethics. Part IV, provision 67

I think, therefore I exist.

R. Descartes

General nature and purpose of the study

This small book was born out of a series of public lectures given by a theoretical physicist to an audience of four hundred people, which did not shrink even after the initial warning about the complexity of the subject and that the lectures could not be called popular, although they practically did not use the physicist's most terrible weapon, mathematical deduction - not because the subject can be explained without the use of mathematics, but simply because it is too confusing for a complete mathematical description. Another feature that gave the lectures a certain popular flavor was the lecturer’s intention to explain to both biologists and physicists a fundamental idea that lies at the intersection of biology and physics.

In fact, despite the variety of topics covered, the idea is intended to convey only one idea - a small commentary on a large and important issue. To avoid getting lost, let's make a short plan.

The big, important and highly debated question is this:

How do physics and chemistry explain events in space and time that occur within the spatial framework of a living organism?

The preliminary answer that this book attempts to establish and justify can be summarized as follows:

The obvious inability of modern physics and chemistry to explain such phenomena does not mean at all that these sciences cannot explain them.

Statistical physics. Fundamental difference in structure

This remark would be quite trivial if its sole purpose was to awaken hope for achieving in the future what was not achieved in the past. However, its meaning is much more optimistic: this inability has a detailed explanation.

Today, thanks to the brilliant work of biologists, mostly geneticists, over the last thirty to forty years, we know enough about the actual material structure of organisms and their workings to state and give the exact reason why: modern physics and chemistry cannot explain space-time events , occurring in a living organism.

The interactions of atoms in the vital parts of the body are fundamentally different from all the connections of atoms that have hitherto been the object of experimental and theoretical research by physicists and chemists. However, this difference, which I consider fundamental, may seem of little significance to anyone except a physicist who realizes that the laws of chemistry and physics are purely statistical. After all, it is from a statistical point of view that the structure of the vital parts of living organisms is so different from any piece of matter with which we, physicists and chemists, work physically in laboratories or mentally at a desk. It is impossible to imagine that the laws and regularities discovered in this way can be directly applied to the behavior of systems that do not have the structure on which they are based.

What is life?

Lectures given at Trinity College, Dublin in February 1943.

Moscow: State Publishing House of Foreign Literature, 1947 - p.150

Erwin Schrödinger

Professor at the Dublin Research Institute

WHAT IS LIFE

from a physics point of view?

WHAT IS LIFE?

The Physical Aspect of the

Living Cell

BRWIN SGHRODINGER

Senior Professor at the Dublin Institute for Advanced Studies

Translation from English and afterword by A. A. MALINOVSKY

Artist G. Riftin

Introduction

Homo liber nulla de re minus quam

de morte cogitat; et ejus sapientia

non mortis sed vitae meditatio est.

Spinoza, Ethica, P. IV, Prop. 67.

A free man is nothing like that

little does not think about death, and

his wisdom lies in reflection

not about death, but about life.

Spinoza, Ethics, Part IV, Theor. 67.

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Preface

It is generally believed that a scientist must have a thorough first-hand knowledge of a particular field of science, and it is therefore believed that he should not write on such matters in which he is not an expert. This is seen as a matter of noblesse oblige. However, in order to achieve my goal, I want to renounce noblesse and ask, in this regard, to release me from the obligations arising from it. My apologies are as follows.

We have inherited from our ancestors a keen desire for unified, all-encompassing knowledge. The very name given to the highest institutions of knowledge - universities - reminds us that from ancient times and for many centuries the universal nature of knowledge was the only thing in which there could be complete trust. But the expansion and deepening of various branches of knowledge during the last hundred wonderful years has presented us with a strange dilemma. We clearly feel that we are only now beginning to acquire reliable material in order to unite into one whole everything that we know; but on the other hand, it becomes almost impossible for one mind to completely master more than any one small specialized part of science.

I see no way out of this situation (without our main goal being lost forever) unless some of us venture to undertake a synthesis of facts and theories, even though our knowledge in some of these areas is incomplete and obtained at second hand and at least we ran the risk of appearing ignorant.

Let this serve as my apology.

Difficulties with language are also of great importance. Everyone’s native language is like a well-fitting garment, and you cannot feel completely free when your language cannot be at ease and when it must be replaced by another, new one. I am very grateful to Dr Inkster (Trinity College, Dublin), Dr Padraig Brown (St Patrick's College, Maynooth) and last but not least, Mr S. C. Roberts. They had a lot of trouble trying to fit me into new clothes, and this was aggravated by the fact that sometimes I did not want to give up my somewhat “original” personal style. If any of it survives despite the efforts of my friends to soften it, it must be attributed to me, and not to theirs.

It was originally assumed that the subheadings of numerous sections would have the nature of summary inscriptions in the margins, and the text of each chapter should be read in continue (continuously).

I am greatly indebted to Dr. Darlington and the publisher Endeavor for the illustration plates. They retain all the original details, although not all of these details are relevant to the content of the book.

Dublin, September, 1944. E. Sh.

A classical physicist's approach to the subject

Cogito, ergo sum

General nature and objectives of the study

This small book arose from a course of public lectures given by a theoretical physicist to an audience of about 400 people. The audience almost did not decrease, although from the very beginning it was warned that the subject of presentation was difficult and that the lectures could not be considered popular, despite the fact that the most terrible tool of a physicist - mathematical deduction - could hardly be used here. And not because the subject is so simple that it can be explained without mathematics, but rather the opposite - because it is too complicated and not entirely accessible to mathematics. Another feature that gave at least the appearance of popularity was the intention of the lecturer to make the main idea associated with both biology and physics clear to both physicists and biologists.

Indeed, despite the variety of topics included in the book, as a whole it should convey only one idea, only one small explanation of a large and important issue. In order not to deviate from our path, it will be useful to briefly outline our plan in advance.

The big, important and very often discussed question is this: how can physics and chemistry explain those phenomena in space and time that take place inside a living organism?

The preliminary answer that this little book will try to give and develop can be summed up as follows: the obvious inability of modern physics and chemistry to explain such phenomena gives absolutely no reason to doubt that they can be explained by these sciences.

Statistical physics. The main difference is in the structure

The foregoing remark would be very trivial if it were intended only to stimulate the hope of achieving in the future what was not achieved in the past. It, however, has a much more positive meaning, namely, that the inability of physics and chemistry to date to provide an answer is completely understandable.

Thanks to the skillful work of biologists, mainly geneticists, over the last 30 or 40 years, enough has now been known about the actual material structure of organisms and their functions to understand why modern physics and chemistry could not explain the phenomena in space and time that occur within living things. body.

The arrangement and interaction of atoms in the most important parts of the body are radically different from all those arrangements of atoms with which physicists and chemists have hitherto dealt in their experimental and theoretical research. However, this difference, which I just called fundamental, is of a kind that can easily seem insignificant to anyone except a physicist, imbued with the idea that the laws of physics and chemistry are thoroughly statistical. It is from a statistical point of view that the structure of the most important parts of a living organism is completely different from any piece of matter with which we, physicists and chemists, have hitherto dealt, practically - in our laboratories and theoretically - at our desks. Of course, it is difficult to imagine that the laws and rules that we have discovered would be directly applicable to the behavior of systems that do not have the structures on which these laws and rules are based.

It cannot be expected that a non-physicist could grasp (let alone appreciate) the entire difference in “statistical structure” formulated in terms so abstract as I have just done. To give life and color to my statement, let me first draw attention to something that will be explained in detail later, namely, that the most essential part of a living cell - the chromosomal thread - can justifiably be called an aperiodic crystal. In physics, we have so far dealt only with periodic crystals. To the mind of a simple physicist they are very interesting and complex objects; they constitute one of the most fascinating and complex structures with which inanimate nature confounds the intellect of the physicist; however, in comparison with aperiodic crystals they seem somewhat elementary and boring. The difference in structure here is the same as between ordinary wallpaper, in which the same pattern is repeated at regular intervals again and again, and a masterpiece of embroidery, say, a Raphael tapestry, which produces not boring repetition, but complex, consistent and full of meaning a drawing drawn by a great master.

The most essential part of a living cell - the chromosome thread - can be called an aperiodic crystal. In physics, we have so far dealt only with periodic crystals. It is therefore not very surprising that the organic chemist has already made a large and important contribution to the solution of the problem of life, while the physicist has made almost nothing.

Why are atoms so small? Many examples have been offered to make this fact clear to the general public, but none has been more striking than that once given by Lord Kelvin: suppose you could put labels on all the molecules in a glass of water; after that you will pour the contents of the glass into the ocean and thoroughly mix the ocean so as to distribute the marked molecules evenly in all the seas of the world; If you then take a glass of water anywhere, anywhere in the ocean, you will find in this glass about a hundred of your marked molecules.

All our sense organs, composed of innumerable atoms, are too crude to perceive the blows of a single atom. We cannot see, hear, or feel individual atoms. Does it have to be this way? If this were not the case, if the human organism were so sensitive that a few atoms or even a single atom could make a noticeable impression on our senses, what would life be like!

There is only one and only thing of special interest to us about ourselves, and that is what we can feel, think and understand. In relation to those physiological processes that are responsible for our thoughts and feelings, all other processes in the body play a supporting role, at least from a human point of view.

All atoms go through completely random thermal motions all the time. Only in the combination of a huge number of atoms do statistical laws begin to operate and control the behavior of these associations with a precision that increases with the number of atoms involved in the process. It is in this way that events acquire truly natural features. The accuracy of physical laws is based on the large number of atoms involved.

The degree of inaccuracy that should be expected in any physical law is √n. If a certain gas at a certain pressure and temperature has a certain density, then I can say that inside a certain volume there are n molecules of gas. If at some point in time you can check my statement, you will find it inaccurate, and the deviation will be of the order of √n. Therefore, if n = 100, you would find the deviation to be approximately 10. So the relative error here is 10%. But if n = 1 million, you would probably find the deviation to be about 1000, and thus the relative error equals 0.1%.

An organism must have a relatively massive structure in order to enjoy the prosperity of quite precise laws both in its internal life and in its interaction with the outside world. Otherwise the number of particles involved would be too small and the “law” too imprecise.

Chapter II. Mechanism of heredity

Above we came to the conclusion that organisms with all the biological processes occurring in them must have a very “polyatomic” structure, and for them it is necessary that random “monatomic” phenomena do not play too big a role in them. We now know that this view is not always correct.

Let me use the word "pattern" of an organism to designate not only the structure and functioning of the organism in adulthood or at any other specific stage, but the organism in its ontogenetic development, from the fertilized egg to the stage of maturity when it begins to reproduce. It is now known that this entire holistic plan in four dimensions (space + time) is determined by the structure of just one cell, namely the fertilized egg. Moreover, its nucleus, or more precisely, a pair of chromosomes: one set comes from the mother (egg cell) and one from the father (fertilizing sperm). Each complete set of chromosomes contains the entire code stored in the fertilized egg, which represents the earliest stage of the future individual.

But the term encryption code is, of course, too narrow. Chromosomal structures serve at the same time as instruments that carry out the development that they foretell. They are both the code of laws and the executive power, or, to use another comparison, they are both the plan of the architect and the forces of the builder at the same time.

How do chromosomes behave during ontogenesis? The growth of an organism is carried out by successive cell divisions. This cell division is called mitosis. On average, 50 or 60 successive divisions are sufficient to produce the number of cells present in an adult.

How do chromosomes behave in mitosis? They are doubled, both sets are doubled, both copies of the cipher. Each, even the least important individual cell necessarily has a full (double) copy of the encryption code. The only exception to this rule is reduction division or meiosis.

One set of chromosomes comes from the father, one from the mother. Neither chance nor fate can prevent this. But when you trace the origin of your heredity back to your grandparents, the matter turns out to be different. For example, a set of chromosomes that came to me from my father, in particular chromosome No. 5. This will be an exact copy of either the No. 5 that my father received from his father, or the No. 5 that he received from his mother. The outcome of the case was decided (with a 50:50 chance). Exactly the same story could be repeated regarding chromosomes No. 1, 2, 3... 24 of my paternal set and regarding each of my maternal chromosomes.

But the role of chance in the mixing of grandfather's and grandmother's heredity in descendants is even greater than it might seem from the previous description, in which it was tacitly assumed or even directly stated that certain chromosomes came as a whole either from the grandmother or from the grandfather; in other words, that single chromosomes arrived undivided. In reality this is not or is not always the case. Before diverging in a reduction division, say, in the one that occurred in the paternal body, each two “homologous” chromosomes come into close contact with each other and sometimes exchange significant parts of themselves with each other. The phenomenon of crossing over, being not too rare, but not too frequent, provides us with the most valuable information about the location of properties in chromosomes.

Maximum gene size. A gene—the material carrier of a certain hereditary trait—is equal to a cube with a side of 300 Å. 300 Å is only about 100 or 150 atomic distances, so the gene contains no more than a million or several million atoms. According to statistical physics, such a number is too small (in terms of √n) to give rise to orderly and regular behavior.

Chapter III. Mutations

We now definitely know that Darwin was wrong when he believed that the material on which natural selection operates is the small, continuous, random changes that are sure to occur even in the most homogeneous population. Because it has been proven that these changes are not hereditary. If you take a crop of pure barley and measure the awn length of each ear, and then plot the result of your statistics, you will get a bell-shaped curve (Figure 3). In this figure, the number of ears with a certain awn length is plotted against the corresponding awn length. In other words, the known average length of the spines predominates, and deviations in both directions occur with certain frequencies. Now select a group of ears, indicated in black, with awns noticeably longer than average, but a group large enough that when sown in the field it will produce a new crop. In a statistical experiment like this, Darwin would have expected the curve to shift to the right for a new crop. In other words, he would expect selection to produce an increase in the average size of the awns. However, in reality this will not happen.

Selection fails because small, continuous differences are not inherited. They are obviously not determined by the structure of the hereditary substance, they are random. The Dutchman Hugode-Fries discovered that in the offspring of even completely pure strains a very small number of individuals appear - say, two or three in tens of thousands - with small but “leap-like” changes. The expression “spasmodic” here does not mean that the changes are very significant, but only the fact of discontinuity, since there are no intermediate forms between the unchanged individuals and the few changed ones. De Vries called it a mutation. The essential feature here is precisely the intermittency. In physics, it resembles quantum theory - there, too, there are no intermediate steps between two adjacent energy levels.

Mutations are inherited as well as the original unchanged characteristics. A mutation is definitely a change in the hereditary baggage and must be due to some change in the hereditary substance. Because of their ability to actually be transmitted to descendants, mutations also serve as suitable material for natural selection, which can work on them and produce species, as described by Darwin, eliminating the unadapted and preserving the fittest.

A specific mutation is caused by a change in a specific region of one of the chromosomes. We know for sure that this change occurs only in one chromosome and does not occur simultaneously in the corresponding “locus” of the homologous chromosome. In a mutant individual, the two “copies of the encryption code” are no longer the same; they represent two different "interpretations" or two "versions".

The version followed by an individual is called dominant, the opposite is called recessive; in other words, a mutation is called dominant or recessive depending on whether it shows its effect immediately or not. Recessive mutations are even more common than dominant mutations and can be quite important, although they are not immediately detected. To change the properties of an organism, they must be present on both chromosomes.

The version of the encryption code - be it original or mutant - is usually denoted by the term allele. When the versions are different, as shown in Fig. 4, the individual is said to be heterozygous for that locus. When they are the same, as, for example, in unmutated individuals or in the case shown in Fig. 5, they are called homozygous. Thus, recessive alleles affect traits only in the homozygous state, whereas dominant alleles produce the same trait in both the homozygous and heterozygous states.

Individuals can be completely similar in appearance and, however, differ hereditarily. The geneticist says that individuals have the same phenotype, but different genotypes. The content of the previous paragraphs can thus be summarized in a brief but highly technical expression: a recessive allele affects the phenotype only when the genotype is homozygous.

The percentage of mutations in the offspring - the so-called mutation rate - can be increased many times the natural mutation rate by shining the parents with x-rays or y-rays. Mutations caused in this way do not differ in any way (except for a higher frequency) from those that arise spontaneously.

Chapter IV. Quantum mechanics data

In the light of modern knowledge, the mechanism of heredity is closely related to the basis of quantum theory. The greatest discovery of quantum theory was its discrete features. The first case of this kind concerned energy. A large-scale body changes its energy continuously. For example, a pendulum that begins to swing gradually slows down due to air resistance. Although this is quite strange, we have to accept that a system with the size of an atomic order behaves differently. A small system, by its very essence, can be in states that differ only in discrete amounts of energy, called its specific energy levels. The transition from one state to another is a somewhat mysterious phenomenon commonly referred to as a “quantum leap.”

Among the discontinuous series of states of a system of atoms, it is not necessary, but still possible, to exist the lowest level, which involves the close approach of the nuclei to each other. Atoms in this state form a molecule. The molecule will have a known stability; its configuration cannot change, at least until it is supplied from the outside with the energy difference necessary to “raise” the molecule to the nearest, higher level. Thus, this difference in levels, which is a completely definite value, quantitatively characterizes the degree of stability of the molecule.

At any temperature (above absolute zero) there is a certain, greater or lesser, probability of rising to a new level, and this probability, of course, increases with increasing temperature. The best way to express this probability is to indicate the average time that should be waited until the rise occurs, that is, to indicate the "waiting time." The waiting time depends on the ratio of two energies: the energy difference required for the rise (W), and the intensity of thermal motion at a given temperature (we denote by T the absolute temperature and by kT this characteristic; k is Boltzmann’s constant; 3/2kT represents the average kinetic energy gas atom at temperature T).

It is surprising how much the waiting time depends on relatively small changes in the W:kT ratio. For example, for W that is 30 times kT, the waiting time will be only 1/10 of a second, but it rises to 16 months when W is 50 times kT, and to 30,000 years when W is 60 times kT .

The reason for the sensitivity is that the waiting time, let's call it t, depends on the ratio W:kT as a power function, that is

(1) t= τe^(W/kT)

τ is some small constant of the order of 10–13 or 10–14 seconds. This factor has a physical meaning. Its value corresponds to the order of the period of oscillations that occur in the system all the time. You could, generally speaking, say: this factor means that the probability of accumulating the required quantity W, although very small, is repeated again and again “at each vibration”, i.e. about 1013 or 1014 times during every second.

The power function is not a random feature. It is repeated again and again in the statistical theory of heat, forming, as it were, its backbone. This is a measure of the improbability that an amount of energy equal to W could accumulate by chance in some specific part of the system, and it is this improbability that increases so much when the average energy kT is required to exceed the threshold W by many times.

Proposing these considerations as a theory of molecular stability, we tacitly accepted that the quantum leap, which we call “ascent,” leads, if not to complete disintegration, then at least to a significantly different configuration of the same atoms - to an isomeric molecule, as said would be a chemist, that is, to a molecule consisting of the same atoms, but in a different arrangement (in application to biology, this could represent a new “allele” of the same “locus”, and a quantum leap would correspond to a mutation).

The chemist knows that the same group of atoms can combine in more than one way to form molecules. Such molecules are called isomeric, i.e., consisting of the same parts.

The remarkable fact is that both molecules are very stable - both behave as if they were the "lowest level". There are no spontaneous transitions from one state to another. When applied to biology, we will be interested only in transitions of this “isomeric” type, when the energy required for the transition (the quantity denoted by W) is not actually a difference in levels, but a step from the initial level to the threshold. Transitions without a threshold between the initial and final states are of no interest at all, and not only in relation to biology. They really don't change anything about the chemical stability of the molecules. Why? They do not have a lasting effect and go unnoticed. For when they occur, they are almost immediately followed by a return to the original state, since nothing prevents such a return.

Chapter V. Discussion and verification of Delbrück's model

We will accept that in its structure the gene is a giant molecule, which is capable only of intermittent changes, reduced to the rearrangement of atoms with the formation of an isomeric molecule (for convenience, I continue to call this an isomeric transition, although it would be absurd to exclude the possibility of any exchange with the environment ).The energy thresholds separating a given configuration from any possible isomeric ones must be high enough (relative to the average thermal energy of an atom) to make transitions rare events. We will identify these rare events with spontaneous mutations.

It has often been asked how such a tiny particle of matter - the nucleus of a fertilized egg - can contain a complex encryption code that includes the entire future development of the organism? A well-ordered association of atoms, endowed with sufficient stability to maintain its orderliness for a long time, seems to be the only conceivable material structure in which the variety of possible (“isomeric”) combinations is large enough to contain a complex system of “determinations” within a minimal space.

Chapter VI. Order, disorder and entropy

From the general picture of hereditary matter drawn in Delbrück’s model, it follows that living matter, although it does not escape the action of the “laws of physics” established to date, apparently contains within itself hitherto unknown “other laws of physics.” Let's try to figure this out. In the first chapter it was explained that the laws of physics as we know them are statistical laws. They relate to the natural tendency of things to become disordered.

But in order to reconcile the high stability of the carriers of heredity with their small size and circumvent the tendency towards disorder, we had to “invent the molecule,” an unusually large molecule, which should be a masterpiece of the highly differentiated order protected by the magic wand of quantum theory. The laws of chance are not devalued by this “invention,” but their manifestation changes. Life represents the ordered and regular behavior of matter, based not only on the tendency to move from order to disorder, but partly on the existence of order, which is maintained all the time.

What is the characteristic feature of life? When we say about a piece of matter, is it alive? When it continues to “do something”, move, exchange substances with the environment, etc. - and all this for a longer time than we would expect an inanimate piece of matter to do under similar conditions. If an inanimate system is isolated or placed in homogeneous conditions, all movement usually very soon ceases as a result of various kinds of friction; differences in electrical or chemical potentials are equalized, substances that tend to form chemical compounds form them, the temperature becomes uniform due to thermal conductivity. After this, the system as a whole fades away, turning into a dead inert mass of matter. An unchanging state is reached in which no noticeable events occur. The physicist calls this a state of thermodynamic equilibrium or “maximum entropy.”

It is precisely because the body would avoid a strict transition to the inert state of “equilibrium” that it seems so mysterious: so mysterious that from ancient times human thought has assumed that some special, non-physical, supernatural force operates in the body.

How does a living organism avoid the transition to equilibrium? The answer is simple: through eating, drinking, breathing and (in the case of plants) assimilation. This is expressed by a special term - metabolism (from the Greek - change or exchange). Exchange of what? Originally, without a doubt, metabolism was meant. But it seems absurd that it is metabolism that is essential. Any atom of nitrogen, oxygen, sulfur, etc. as good as any other of the same kind. What could be achieved by their exchange? What then is that precious something contained in our food that protects us from death?

Every process, phenomenon, event, everything that happens in nature means an increase in entropy in the part of the world where it happens. Likewise, a living organism continuously increases its entropy - or, in other words, produces positive entropy and thus approaches the dangerous state of maximum entropy, which is death. He can avoid this state, that is, remain alive, only by constantly extracting negative entropy from his environment. Negative entropy is what the body feeds on. Or, to put it less paradoxically, the essential thing about metabolism is that the organism manages to rid itself of all the entropy that it is forced to produce while it is alive.

What is entropy? It is not a vague concept or idea, but a measurable physical quantity. At absolute zero temperature (about –273°C), the entropy of any substance is zero. If you change a substance to any other state, the entropy increases by an amount calculated by dividing each small amount of heat expended during this procedure by the absolute temperature at which that heat was expended. For example, when you melt a solid, the entropy increases by the heat of fusion divided by the temperature at the melting point. You can see from this that the unit by which entropy is measured is cal/°C. Much more important for us is the connection of entropy with the statistical concept of order and disorder, a connection discovered by the studies of Boltzmann and Gibbs in statistical physics. It is also an exact quantitative relationship and is expressed

entropy = klogD

where k is Boltzmann's constant and D is a quantitative measure of atomic disorder in the body under consideration.

If D is a measure of disorder, then the reciprocal value 1/D can be considered as a measure of order. Since the logarithm of 1/D is the same as the negative logarithm of D, we can write Boltzmann's equation this way:

–(entropy) = = klog(1/D)

Now the awkward expression “negative entropy” can be replaced by a better one: entropy, taken with a negative sign, is itself a measure of order. The means by which an organism maintains itself constantly at a sufficiently high level of order (= a sufficiently low level of entropy) is actually to continuously extract order from its environment (for plants, their own powerful source of “negative entropy” is, of course, sunlight) .

Chapter VIII. Is life based on the laws of physics?

Everything we know about the structure of living matter leads us to expect that the activity of living matter cannot be reduced to the ordinary laws of physics. And not because there is some “new force” or anything else that controls the behavior of individual atoms within a living organism, but because its structure is different from everything we have studied so far.

Physics is governed by statistical laws. In biology we encounter a completely different situation. A single group of atoms, existing in only one copy, produces regular phenomena, wonderfully tuned one in relation to the other and in relation to the external environment, according to extremely subtle laws.

Here we encounter phenomena, the regular and natural development of which is determined by a “mechanism” that is completely different from the “mechanism of probability” of physics. In each cell the guiding principle is contained in a single atomic association, existing in only one copy, and it directs events that serve as a model of order. This is not observed anywhere except in living matter. The physicist and chemist, while studying inanimate matter, have never encountered phenomena that they had to interpret in this way. Such a case has not yet arisen, and therefore the theory does not cover it - our beautiful statistical theory.

The orderliness observed in the unfolding of the life process arises from another source. It turns out that there are two different “mechanisms” that can produce ordered phenomena: a “statistical mechanism” that creates “order out of disorder,” and a new mechanism that produces “order out of order.”

To explain this we must go a little further and introduce a clarification, not to say an improvement, into our previous statement that all physical laws are based on statistics. This statement, repeated again and again, could not but lead to controversy. For there are indeed phenomena whose distinctive features are clearly based on the principle of "order from order" and seem to have nothing to do with statistics or molecular disorder.

When does a physical system exhibit a “dynamic law” or “features of a clockwork mechanism”? Quantum theory gives a short answer to this question, namely, at absolute zero temperature. As the temperature approaches zero, molecular disorder ceases to influence physical phenomena. This is the famous “thermal theorem” of Walter Nernst, which is sometimes, and not without reason, given the loud name of the “Third Law of Thermodynamics” (the first is the principle of conservation of energy, the second is the principle of entropy). You should not think that it must always be a very low temperature. Even at room temperature, entropy plays a surprisingly small role in many chemical reactions.

For pendulum clocks, room temperature is practically equivalent to zero. This is the reason that they work "dynamically". Clocks are able to function "dynamically" because they are constructed from solids to avoid the disruptive effects of thermal motion at normal temperatures.

Now, I think, a few words are needed to formulate the similarities between a clock mechanism and an organism. It simply and exclusively boils down to the fact that the latter is also built around a solid body - an aperiodic crystal, forming a hereditary substance that is not primarily subject to the effects of random thermal motion.

Epilogue. On determinism and free will

From what was stated above, it is clear that the spatio-temporal processes occurring in the body of a living being, which correspond to its thinking, self-awareness or any other activity, are, if not completely strictly determined, then at least statistically determined. This unpleasant feeling arises because it is customary to think that such a concept is in conflict with free will, the existence of which is confirmed by direct introspection. Therefore, let's see if we can't get a correct and consistent conclusion based on the following two premises:

My body functions as a pure mechanism, obeying the universal laws of nature.

However, I know from undeniable, direct experience that I control the actions of my body and foresee the results of those actions. These results can be of great importance in determining my destiny, in which case I feel and consciously take full responsibility for my actions.

It seems to me that from these two premises only one conclusion can be drawn, namely, that the "I", taken in the widest sense of the word - that is, every conscious mind that has ever said or felt "I" - is not nothing more than a subject who can control the “movement of atoms” according to the laws of nature.

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