Physical and biological constraints on cognition

Kleiber’s law in biology states that the specific metabolic rate (metabolic rate per unit mass) scales as M– 1/4 in terms of the mass M of the organism. A paper by ARP Rau looks at this law. In the article he states:

Thus, the rich variety and diversity in biology, including of scaling exponents, has been used to dismiss the search for underlying causes simply as physicists’ hubris. This stance is untenable because, notwithstanding the diversity, there is far too much evidence as already noted from widely disparate biological systems for scaling laws, many of them with the (– 1/4) power. On the other side, it is also an overreach to argue too generally, claiming the same power law for “everything”. This is not how physics fits into biology. Rather, physics comes in especially “at the edges” in constraining the limits into which biological organisms fit since they too are subject to the laws of physics.

What is remarkable about the biological world is that within such limits set by physics, most niches in between seem to have been explored, if not occupied, during the course of biological evolution. A more modest approach, therefore, and the spirit in which this note is advanced, is to see what constraints are set by geometry and by physical laws that are expected to be relevant, and then see what some of the observed biological scalings further imply. (p. 477)

This reflects my thinking on this: physical laws constrain biological phenomenon. They open a 'space of possibilities' and most regions within this space have been explored (or currently occupied) by the evolutionary process.

An interesting speculation is how physics and physiology might constrain possible 'perceptual' or 'representational' or 'cognitive' (in a broad sense) systems. One might suggest - analogously - that given the constraints imposed by biology, which is in turn constrained by physics, there is a space of possible 'epistemic' systems, and most of these have been explored by evolution. The idea of 'cultural evolution' may be a way of extending this idea.