The Roles of Necessity in Biology
Robert Rosén · Birkhäuser Boston eBooks · 1989
Any system is characterized by the entailments mandated within it. In formal systems, these entailments take the form of inferences governed by explicit production rules. In natural systems, entailments are governed by causality. It is an article of faith in science that the two modes of entailment can be brought into a congruence in such a way that inference in a formalism mirrors causality in the world, and conversely. This congruence is explicitly embodied in a modelling relation between a natural system and a formalismWe investigate the entailment structure characteristic of modern physics, which we argue is surprisingly weak. In fact, it manifests itself entirely in a recursive sequence of state transitions, which is itself determined by things unentailed within the formalism. This weakness in entailment makes the formalism appear very general, in terms of what can be encoded into it, but makes the formalism very special as a formalism. We contrast it with the entailments required in biology on the one hand, and with the much broader province of causality originally envisioned by Aristotle, and argue that (a) biology requires modes of entailment not presently available in any physical formalism, and (b) the old Aristotelian view of causality is far more consonant with the exigencies of biology. We indicate a way in which these several observations might be consistently reconciled.