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.
Wednesday, February 14, 2007
Monday, February 12, 2007
What are we conscious of? 2
This article by Alva Noƫ does a good job in explaining my intuition expressed in the last blog. It takes an 'enactive' approach to visual Alva perception, and places emphasis on sensori-motor skills, and being aware of detail on a 'need to know' basis.
http://www.imprint.co.uk/pdf/NOE.PDF
http://www.imprint.co.uk/pdf/NOE.PDF
Sunday, February 11, 2007
What are we conscious of?
Prof. Radu Bogdan proposed the following schema in last Friday's philosophy of mind seminar: a mental representation [has a] content [which is about] a target. He suggested that we were conscious of contents, not targets. This seems like a curious claim. Aren't we aware of objects of knowledge - objects that exist with objective properties - rather than our mental representations. For instance, we don't see ellipses when we see coins lying on tables, we see coins which are circular. When we dream in a sense we see only 'mental contents' but when we perceive (successfully) we do not: we see the object of perception. It's like using our hands to feel the shape of something; our eyes are used to inform us of objective properties of our environments.
It's not altogether clear to me how to draw the distinction between contents and targets in fact. There must be research on this: what are we generally aware of: objects and their objective properties, or representations and their content? My feeling is that if we went around being aware of contents and not things, we'd be suffering from something like 'derealisation', the clinical condition.
It's not altogether clear to me how to draw the distinction between contents and targets in fact. There must be research on this: what are we generally aware of: objects and their objective properties, or representations and their content? My feeling is that if we went around being aware of contents and not things, we'd be suffering from something like 'derealisation', the clinical condition.
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