Close
A lot has been written in the philosophical literature about conscious experience being some form of 'emergent' property of a complex physical system. This suggestion rather assumes that conscious experience does not occur in simple things like atoms. It is unclear how we could know that but it does seem reasonable to suggest that something in a brain is set up to experience in a way that is more interesting than anything in a rock.
The consensus of opinion has tended to be sceptical about the existence of 'radical emergence' defined in terms of some totally new property emerging with complexity that is quite independent of the properties of the units from which a complex system is made up. However, there are two reasons why I think we should be careful about drawing such a conclusion. The first is that, as I understand it, modern physics is much less exclusively 'reductive' than philosophers tend to think. Rather than considering the universe as built up of a myriad of particles it tends more towards seeing the particles as arising as asymmetries of an initial whole. Rather than seeing large things as emergent we might better consider them as 'less divided' or even 'immergent'. The second is that, as John Heil has pointed out, the problem with understanding human subjectivity is not so much an issue of the dynamic properties involved as one of understanding what sort of entity could have such properties. What we may be looking for is not so much an emergent property of something as an emergent entity that has the new property we are looking for.
As an example, molecules made up of fewer than five atoms connected in a particular sequence can only have one form (as a rule). However, with five or more it is possible to have 'left handed and right handed' forms. This 'chirality' is a property that does not seem to arise from any property of components. Similarly the fact that 23 is a prime number does not seem to depend on features of its parts. A number might not seem to be concrete enough to be relevant. However, the number 60 has the unique property of being the number of carbon atoms needed to produce an icosahedral Buckminsterfullerene molecule. One more or one less is no good. Nor is this just a matter of ten lots of six or twelve lots of five. The 'sixtyness' of the icosahedron is an irreducible feature of the structure of three dimensional relations.
Virtually all features of the everyday world we inhabit are determined directly or indirectly by the way that 'valency' electrons (those most loosely associated with single atoms) settle into the most stable (energy minimum) domains available to them. These domains are affected by the ordered structure of objects at every level of size, particularly in metals and crystalline or semi-crystalline structures. As things get larger, domains become available that are determined directly by the macroscopic structure of the object. The dynamic modes that these domains provide are effectively 'emergent entities'. It seems not unreasonable to suggest that highly ordered biological structures like cells may be inhabited by such entities of a more interesting sort than rocks.
An important aspect of the dynamic domains that arise with larger ordered structures, in respect to Heil's point, is that although these may have complexity in their structural parameters they have no parts. They are individual indivisible entities. This gets round the problem with attributing experience to systems of units related by sequential causal interaction, as for neural networks, which are aggregates of parts that we may consider as 'whole systems' but on a worrying arbitrary basis. Any theory that attributes experience to systems with parts has to provide an explanation for how the 'proto-experiential' contributions of the parts 'combine'. There seems to be no way of accounting for this in physical terms.
