One of the central things in the Schrödinger's little book What Is Life is what he has to say about the chromosomes containing the program or the code, and he says here… on page 20, he says: 'In calling the structure of the chromosome fibres a code script, we mean that the all penetrating mind once conceived by Laplace, to which every cause or connection lay immediately open, could tell from their structure whether the egg would develop under suitable conditions, into a black cock, or into a speckled hen, into a fly, or a maize plant, a rhododendron, a beetle, a mouse or a woman'. Now, apart from the list of organisms he has given, which falls short of a serious classification of the living world, what he is saying here is that if you could look at the chromosomes, you could compute the… you could calculate the organism, but he's saying something more. He's saying that you could actually implement the organism because he goes on to add: 'But the term code script is of course too narrow. The chromosome structures are at the same time instrumental in bringing about the development they foreshadow. They are law code and executive power, or to use another simile they are architect's plan and builder's craft in one.' What he is saying here is that the chromosomes not only contain a description of the future organism but the means to implement that description or program as we might call it. That's wrong, because they don't contain the means to implement it, they only contain a description of the means to implement it and that distinction was made absolutely crystal clear by this remarkable paper of von Neumann, in which he develops and in fact provides a proof of what a self-reproducing automaton – or machine – would have to… would have to contain in order to satisfy the requirements of self-reproduction. He develops this concept of course from the earlier concept of Turing, who had developed ideas of automata that operated on tapes and which of course gave a mechanical example of how you might implement some computation. And if you like, this is the beginning of the theory of computation and what von Neumann has to say about this is made very clear in this essay. And he says that you've got to have several components, and I'll just summarise them. He said you first start with an automaton A, 'which, when furnished this description of any other automaton in terms of the appropriate functions, will construct that entity'. It's like a Turing machine, you see. So automaton A has to be given a tape and then it'll make another automaton A, all right. Now what you have, you've got to have… add to this automaton B. 'Automaton B can make a copy of any instruction I that is furnished to it', so if you give it a program, it'll copy the program. And then you have… you combine A and B with each other and you give a control mechanism C, that you have to add as well, which does the following. It says, 'Let A be furnished with the instruction I'. So you give... you give the tape to A, A copies it under the control of C, okay, by every description, so it makes another copy of A, then you… and of course B is part of A. Then you… C then tells B, 'copy this tape I', gives B the copying part of it, this copies it and then C will then take the tape I, and put it into the new machine, okay, and turns it loose as he says here, 'as an independent entity'.
