The use of informational terms is widespread in molecular and developmental biology. The usage
dates back to Weismann. In both protein synthesis and in later development, genes are symbols, in
that there is no necessary connection between their form (sequence) and their effects. The sequence
of a gene has been determined by past natural selection, because of the effects it produces. In
biology, the use of informational terms implies intentionality, in that both the form of the signal,
and the response to it, have evolved by selection. Where an engineer sees design, a biologist sees
natural selection.
A central idea in contemporary biology is that of information. Developmental biology can be seen
as the study of how information in the genome is translated into adult structure, and evolutionary
biology of how the information came to be there in the first place. Our excuse for writing a chapter
concerning topics as diverse as the origins of genes, of cells, and of language is that all are
concerned with the storage and transmission of information.
(Szathmáry and Maynard Smith, 1995)Let us begin with the notions involved in classical information theory…These concepts do
not apply to DNA because they presuppose a genuine information system, which is composed of a coder,
a transmitter, a receiver, a decoder, and an information channel in between. No such components are
apparent in a chemical system (Apter and Wolpert, 1965). To describe chemical processes with the
help of linguistic metaphors such as “transcription” and “translation”
does not alter the chemical nature of these processes. After all, a chemical process is not a signal
that carries a message. Furthermore, even if there were such a thing as information transmission
between molecules, transmission would be nearly noiseless (that is, substantially nonrandom), so
that the concept of probability, central to the theory of information, does not apply to this kind
of alleged information transfer.
(Mahner and Bunge, 1997)It is clear from these quotations that there is something to talk about. I shall be concerned
only with the use of information concepts in genetics, evolution, and development, and not in
neurobiology, which I am not competent to discuss.