Consciousness

• seCtIon FoUR: eVoLUtIon
  a brain error, but a useful and efficient adaptation: con-
  sciousness has adaptive functions (both biological and
  social), even if we could also describe it as, in one sense,
  illusory.
  In fully illusionist theories, there is no need to explain how
  ‘consciousness itself ’ or phenomenal experience evolved,
  because they did not. What evolved was our propensity
  to mischaracterise our own minds, creating the illusion
  of duality and inventing the hard problem. The nature,
  function, and origin of these illusions differs between the
  theories, but they all assume that evolution means biolog-
  ical evolution based on genes. There is an alternative and
  broader view of evolution based on what Dawkins (1976)
  calls ‘Universal Darwinism’.

UNIVERSAL DARWINISM

The process of natural selection can be thought of as a

simple algorithm: if you have variation, selection, and

heredity, then you must get evolution (Chapter  10). This

means that evolution can work on anything that is varied

and selectively copied. In other words, there can be other

replicators and other evolutionary systems. This is the

principle of universal Darwinism.

Are there any other evolutionary processes? The answer is

yes. Many processes once thought to work by instruction

or teaching turn out to work by selection from pre-exist-

ing variation. This is true of the immune system and of many aspects of develop-

ment and learning (Gazzaniga, 1992). For example, the development of young

brains involves the selective death of many neurons and connections; learning

to speak involves generating all kinds of strange noises and then selecting from

those. Dennett (1995a) provides an evolutionary framework for understanding

the various design options available for brains, with each level empowering the

organisms to find better and better design moves. He calls it the ‘Tower of Gener-

ate-and-Test’. At each level, new variants are generated and then tested. By using

the same Darwinian process in new ways, new kinds of minds are created.

Of particular interest here are Darwinian theories of brain function. One example

is Gerald Edelman’s (1989) theory of neural Darwinism or neuronal group selec-

tion, which forms the basis for Edelman and Tononi’s (2000a) integrated infor-

mation theory of consciousness (Chapter  5). It depends on three main tenets.

‘Developmental selection’ occurs when the brain is growing and neurons send

out branches in many directions, providing enormous variability in connection

patterns. These are then pruned, depending on which are most used, to leave

long-lasting functional groups. A  similar process of ‘experiential selection’ goes

on throughout life, with certain synapses within and between groups of locally

coupled neurons being strengthened and others weakened, without changes in

the anatomy.

FIGURE 11.10 • Tower of Generate-and-Test.