AJP - Regulatory, Integrative and Comparative Physiology, Vol 238, Issue 5 277-R290, Copyright © 1980 by American Physiological Society
Physical causality and brain theories
F. E. Yates
The history of deterministic theories in physics is reviewed, and four
levels of determinism are found: 1) absolute, 2) asymptotic, 3)
probabilistic, and 4) absolute indeterminism. Nagel's view that all causal
laws are deterministic in the frame of the state descriptions to which they
refer is acknowledged, but the inevitability of macroscopic measurement
noise may hint that dynamical laws are innately noisy. Quantum mechanical
effects are not the noise source. Symmetry and broken symmetry are
introduced as physical concepts that can account both for lawfulness, and
for the hierarchical nature of the universe. Physical ideas are chosen over
those of formal systems with indirect self-reference as the basis of a
global theory of brains. By exclusion it is concluded that only a
statistical thermodynamics, combined with nonlinear mechanics, has the
features needed for theorizing about brains in a physical sense. Quantum
mechanics is judged not to be relevant. New statistical thermodynamic
theories are briefly described, and their strengths and weaknesses noted.
The question, "Why should neuroscience look to physics for its theories?"
is raised and answered. Some concrete objectives for a program of
theoretical research are stated.
