For seven chapters consisting of some 80 pages Schrödinger ambles his way through a fairly prosaic consideration of biology from a physicist’s point of view, only to drop this bomb in his epilogue:

So let us see whether we cannot draw the correct, non-contradictory conclusion from the following two premises:
(i) My body functions as pure mechanism according to the Laws of Nature.
(ii) Yet I know, but 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.

The only possible inference from these two facts is, I think, that I – I in the widest meaning of the word, that is to say, every conscious mind that has ever said or felt 'I' - am the person, if any, who controls the 'motion of the atoms' according to the Laws of Nature.

Heady stuff, even, I dare say, from the man who brought you his eponymous cat, locked in its box waiting forever for its wave-function to collapse so that it might simply live or die. But wait... there’s more...

. . . 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.

How does the idea of plurality. . . arise at all? Consciousness finds itself intimately connected with, and dependent on, the physical state of a limited region of matter, the body. . . . Now, there is a great plurality of similar bodies. Hence the pluralization of consciousness or minds seems a very suggestive hypothesis. Probably all simple, ingenuous people, as well as the great majority of Western philosophers, have accepted it.

It leads almost immediately to the invention of souls, as many as there are bodies, and to the question whether they are mortal as the body is or whether they are immortal and capable of existing by themselves. The former alternative is distasteful, while the latter frankly forgets, ignores or disowns the facts upon which the plurality hypothesis rests. . . .

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.

. . . 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 analyze 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 may acquire new friends, you share life with them as intensely as you never 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 reminisces, you would not find that he had killed you. In no case is there a loss of personal existence to deplore.

Nor will there ever be.

There’s not much more I can say that would further illuminate the above. It has the powerful concision of an elegant mathematical argument, and one would expect no less from Erwin Schrödinger, though one is mightily surprised he ventured into this territory at all. To me, it shows a bravery that most modern day scientists and mathematicians lack; an eagerness to apply his mind’s rigor to questions that may indeed prove unanswerable through reason, though none the less fascinating or important for that. Schrödinger here seems to shrug his shoulders, roll up his sleeves and say, “Why the hell shouldn’t I take a stab at the ultimate question of existence?” I wish more great minds had done the same, though, I suppose if I take Schrödinger’s argument at face value, it really doesn’t matter, since if one mind takes the dare, we all have.

Note: Marluth makes a couple of mistakes in the preceding w/u:

(1) In opposition to what seems to be asserted, Schrödinger observed with some wonder that because the position of each individual atom is so important to the shape, and therefore purpose, of large biochemical molecules (or aperiodic crystals, as he referred to them), quantum fluctuations thus have effects (i.e. mutations) on living tissue much more deeply significant than what could possibly result from the same fluctuations in similarly sized quantities of homogenous inorganic solids (“periodic crystals”).

(2) The notion that “...the author deduces the existance [sic] of genes at a time before there was actual evidence for this...” is obviously absurd, since genes as we know them had been deduced by Gregor Mendel in 1866, though his work was not rediscovered until 1900. Schrödinger even mentions this very fact in Chapter 3.

It should also be noted that What is Life? was originally presented as a series of lectures under the auspices of the Dublin Institute for Advanced Studies at Trinity College, Dublin, in February 1943.