On balance, the cartesian metaphor of organism as machine has proved to be a good idea. Ideas do not have to be correct in order to be good; its only… - Robert Rosen

The physical structures of organisms play only a minor and secondary role... The only requirement which physical structure must fulfill is that it allow the characteristic behaviors themselves to be manifested. Indeed, if this were not so, it would be impossible to understand how a class of systems as utterly diverse in physical structure as that which comprises biological organisms could be recognised as a unity at all.

Perhaps the first lesson to be learned from biology is that there are lessons to be learned from biology.

It is essential to realize at this point that the formalism to be developed, although we cast it initially primarily in the framework of natural systems, is in fact applicable to any situation in which a class of objects is associated with real numbers, or in fact classified or indexed by any set whatever. It is thus applicable to any situation in which classification, or recognition, or discrimination is involved; indeed, one of the aims of our formalism is to point up the essential equivalence of the measurement problem in physics with all types of recognition or classification mechanisms based on observable properties of the objects being recognized or classified.