"WHAT IS LIFE?"

This book was cute, no other way to describe it. It is adorable to see the reaction of a physicist to biology, it is like managing to forget an amazing book you read and reread it (can’t wait to do that with Harry Potter if I ever can) but you get to be re-mindblown by the amazingness of biology by stepping outside of it. The new perspective is beautiful.


The notes below are an abosolute selfish collection of what I resonnated with and refreshed from 6 years ago high-school-physics. It also made me sad that we didn't get to see these sort of applications and interpretations of physics in school: they would've been much more tangible, interesting and concrete than the examples and exercises we had to do.


I don't think there's much value in reading them, but the book is super-short, I would recommend it to anyone with an interest in either field, it's easy enough to follow both in biology and physics, and provides some essential physics concepts for beginners that may just pique your interest in going into quantum and thermodynamics more.


Happy to feel it give me the same unintentional-self-help results physcis always gave :)




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?

Another way to ask - how can there be life.


It is concerned with the size of organisms, more particularly with the size of our own corporeal selves.

Whenever one asks a question why is something so..? Always pick out compared to what does it seem this way.


Only in the co-operation of an enormously large number of atoms do statistical laws begin to operate and control the behaviour of these assemblées with an accuracy increasing as the number of atoms involved increases.

The uncertainty principle places a limit on the behaviour of small particles, if there is a requirement for higher processing and thought (as in the brain) there should be a large enough number of particles for there to be a statistical behaviour allowing control, order and predictability.


The orientation the field tends to produce is continually counteracted by the heat motion, which works for random orientation.

This is why you have supercooled magnets: the force of the magnet is opposed by the heat motion, so the lower the temperature, the stronger the magnetisation without the need for increasing the external field.


But precisely in consequence of this, a plane separating two neighbouring slices will be crossed by more molecules coming from the left than in the opposite direction, simply because to the left there are more molecules engaged in random walk than there are to the right.

Why diffusion happens: if you draw a plane at any point of the container, you would have more molecules crossing the plane from the side with more molecules if they were all moving in a completely random direction.


GOETHE: And what in fluctuating appearance hovers, Ye shall fix by lasting thoughts.


The evidence that two features, similar in appearance, are based on the same principle, is always precarious as long as the principle itself is unknown.


Quantum mechanics is the first theoretical aspect which accounts from first principles for all kinds of aggregates of atoms actually encountered in Nature.


Indeed, what we have learnt at school about molecules does not give the idea that they are more closely akin to the solid state than to the liquid or gaseous state.

In a way: in the case of the liquid or gas, the particles you are considering are the molecules themselves; in the case of the molecule, the whole thing is more similar in nature to a solid (in its stability and energy required to destabilise it) for example

So this would still be true for the molecules themselves in the gas or liquid - but for the thing on the whole, no.


The reason for this is that the atoms forming a molecule, whether there be few or many of them, are united by forces of exactly the same nature as the numerous atoms which build up a true solid, a crystal. The molecule presents the same solidity of structure as a crystal.


The low mutability of wild genes was distinctly increased, but the comparatively high mutability occurring with some of the already mutated genes was not, or at any rate was much less, increased.

When radiating DNA


SPINOZA, Ethics, Pt III, Prop.2 Neither can the body determine the mind to think, nor the mind determine the body to motion or rest or anything else (if such there be).


The laws of physics, as we know them, are statistical laws. They have a lot to do with the natural tendency of things to go over into disorder.


To reconcile the high durability of the hereditary substance with its minute size, we had to evade the tendency to disorder by 'inventing the molecule', in fact, an unusually large molecule which has to be a masterpiece of highly differentiated order, safeguarded by the conjuring rod of quantum theory.

Small things are disordered and cannot be predictable, even if you want a molecule, it has to be a large one to be stable.


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.


The non-physicist finds it hard to believe that really the ordinary laws of physics, which he regards as the prototype of inviolable precision, should be based on the statistical tendency of matter to go over into disorder.


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.

Another argument towards ‘life is movement’ and the only reason we have a brain is to move.


It is by avoiding the rapid decay into the inert state of 'equilibrium' that an organism appears so enigmatic.

ahh what a beautiful way to describe existence


What an organism feeds upon is negative entropy. Or, to put it less paradoxically, the essential thing in metabolism is that the organism succeeds in freeing itself from all the entropy it cannot help producing while alive.


The entropy increases by an amount which is computed by dividing every little portion of heat you had to supply in that procedure by the absolute temperature at which it was supplied and by summing up all these small contributions.


And that we give off heat is not accidental, but essential. For this is precisely the manner in which we dispose of the surplus entropy we continually produce in our physical life process.


This seems to suggest that the higher temperature of the warmblooded animal includes the advantage of enabling it to get rid of its entropy at a quicker rate, so that it can afford a more intense life process.

MIGUEL DE UNAMUNO (quoted from conversation) If a man never contradicts himself, the reason must be that he virtually never says anything at all.

But if you are given a single radioactive atom, its probable lifetime is much less certain than that of a healthy sparrow.

When you work with single/small particles, you lose predictability, their events are only probable.

Reminds me of Feynmans' Not smarter than 65 men, but definitely smarter than the average of 65 men - we can only make predictions on averages.


The physicist and the chemist, investigating inanimate matter, have never witnessed phenomena which they had to interpret in this way. The case did not arise and so our theory does not cover it our beautiful statistical theory of which we were so justly proud because it allowed us to look behind the curtain, to watch the magnificent order of exact physical law coming forth from atomic and molecular disorder; because it revealed that the most important, the most general, the all-embracing law of entropy increase could be understood without a special assumption ad hoc, for it is nothing but molecular disorder itself.


We must therefore not be discouraged by the difficulty of interpreting life by the ordinary laws of physics. For that is just what is to be expected from the knowledge we have gained of the structure of living matter. We must be prepared to find a new type of physical law prevailing in it. Or are we to term it a non-physical, not to say a super-physical, law?


As zero temperature is approached the molecular disorder ceases to have any bearing on physical events.


Consciousness is never experienced in the plural, only in the singular. Even in the pathological cases of split consciousness or double personality the two persons alternate, they are never manifest simultaneously. In a dream we do perform several characters at the same time, but not indiscriminately: we are one of them; in him we act and speak directly, while we often eagerly await the answer or response of another person, unaware of the fact that it is we who control his movements and his speech just as much as our own.