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"Notes on the Book 'What is Life'"

"What is Life" Reading Notes#

Author: [Austria] Erwin Schrödinger
Reading Duration: 1 hour

These are the notes and excerpts I recorded while reading "What is Life" on WeChat Reading.


What is Life?#

A free person rarely thinks about death; his wisdom is not the silent meditation on death, but the contemplation of life.

Existence is eternal; for many laws preserve the treasures of life; and the universe draws beauty from these treasures. — Goethe

The ever-changing phenomena linger, and you will be fixed in eternal thoughts. — Goethe

The increase of mutations is strictly proportional to the dose of radiation, so one can indeed say (as I have said) that it is an increasing coefficient.

Therefore, mutations are not an accumulation effect produced by the mutual enhancement of continuous small doses of radiation. A mutation must occur as a single event in a chromosome during the period of radiation.

If you widely change the nature of the rays (wavelength), from soft X-rays to quite hard gamma rays, the coefficient remains unchanged as long as you give the same dose calculated in the so-called roentgen units, that is, the dose you use is calculated based on the total number of ions produced in a unit volume of a selected standard substance at the place where the organism is irradiated during the exposure.

If ionization (or excitation) occurs within a range not exceeding "ten atomic distances" from a specific point on the chromosome, there is a chance of producing a mutation. We will discuss this in more detail now.

And your spirit's fiery imagination silently conveys an image, a metaphor. — Goethe

Indeed, just as light reveals itself, it also reveals darkness; thus, truth is its own standard, and so is error. — Spinoza, "Ethics," Part II, Proposition 43

The body cannot determine the soul to think, nor can the soul determine the body to move, be still, or engage in other activities. — Spinoza, "Ethics," Part III, Proposition 2

Life seems to be the ordered and regular behavior of matter; it is not entirely based on its tendency from order to disorder, but is partially based on the existing order that is maintained.

In some very advanced countries (I can't remember if it was Germany or the United States, or both), you will find that in restaurants, the menu not only lists prices but also indicates the energy contained in each dish. Needless to say, this is quite absurd. Because the energy contained in an adult organism, like the matter it contains, is fixed and unchanging. Since any calorie is of equal value to any other calorie, it is indeed incomprehensible what pure exchange could be useful for.

Therefore, the clumsy expression of "negative entropy" can be replaced with a better phrase: the entropy with a negative sign, which is itself a measure of order. Thus, an organism stabilizes itself at a relatively high level of order (equivalent to a relatively low level of entropy) by continuously drawing order from its environment. This conclusion is more reasonable than it initially appears. However, it may be criticized for being quite cumbersome. In fact, as far as higher animals are concerned, we know this order, as they completely depend on it; that is to say, the state of matter in the organic substances of varying complexity that they consume as food is highly ordered. After animals utilize this food, what they excrete is greatly degraded material, but not completely decomposed, because plants can still utilize it. (Of course, plants obtain the most powerful supply of "negative entropy" from sunlight.)

If a person never contradicts himself, it must be because he never says anything. — Unamuno

These facts are undoubtedly the most interesting facts revealed by contemporary science. We may find that they are ultimately not unacceptable. An organism concentrates the "flow of order" within itself, thus avoiding a decline into atomic chaos — "drawing order" from a suitable environment — this astonishing gift seems to be related to the existence of "non-periodic solids," namely, chromosome molecules. These solids undoubtedly represent the highest level of ordered atomic aggregates we know — much higher than the order of ordinary periodic crystals — relying on each atom and each free radical playing its role within the solid.

In biology, we face a completely different situation. Single atomic clusters that exist only in one copy orderly produce some events and make incredible adjustments among themselves and with the environment according to the most subtle laws. I say existing only in one copy because we still have examples of eggs and unicellular organisms. In the later stages of higher biological development, the number of copies increases, that is true. But to what extent does it increase? I know that in fully grown mammals, it can reach 10 to the power of 14. What is that? It is only one millionth of the number of molecules in a cubic inch of air. Although the number is quite large, when they coalesce, they only form a small droplet of liquid. Now look at how they are actually distributed. Each cell accommodates exactly one of these copies (or two, if we remember diploids), and since we know that the power of this tiny central organ is in isolated cells, doesn't each cell act like a branch of a local government that conveniently communicates messages using a common code throughout the body?

Precisely because such examples have not been previously proposed, our beautiful statistical theories did not include them. Our statistical theories are something to be proud of because they allow us to see behind the scenes, drawing our attention to the solemn order of precise physical laws derived from the disorder of atoms and molecules; and because they reveal that the most important, most universal, and all-encompassing law of increasing entropy can be understood without special assumptions, as entropy is nothing other than the disorder of the molecules themselves.

However, the view that the friction effects and thermal effects in a clock are negligible may be a practical perspective; while the second view, which does not ignore these effects, is undoubtedly a more fundamental perspective, even when we are faced with a clock powered by a spring moving regularly, this is still a fundamental view. Because it does not believe that the operating mechanism has truly left the statistical nature of the process. The real physical picture includes the possibility that even a normally functioning clock, by consuming thermal energy from the environment, could immediately reverse all its motion and work backward, rewinding its spring. The probability of such an event is exactly "six of one, half a dozen of the other" compared to the "Brownian motion outbreak" of a clock without a driving mechanism.

When does a physical system — an atomic combination of any kind — display "dynamical laws" (in the Planck sense) or "characteristics of clockwork"? Quantum theory has a brief answer to this question: at absolute zero. As the temperature approaches zero, the disorder of molecules no longer has significance for physical events. By the way, this fact was not discovered through theory, but was found by carefully studying chemical reactions over a wide temperature range and extrapolating the results to zero — absolute zero is practically unattainable — and this is the famous "thermal theorem" of W. Nernst, which is not an exaggeration to say that this theorem is sometimes honored with the title of "third law of thermodynamics" (the first law is the principle of energy, the second law is the principle of entropy).


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