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THE CO-EVOLUTION OF MATTER AND CONSCIOUSNESS1
Max Velmans, Goldsmiths, University of London, New Cross, London SE14 6NW;
email [email protected]; web address
http://www.goldsmiths.ac.uk/psychology/staff/velmans.php
Synthesis Philosophica (2007), Vol. 22, No.44, fasc.2, pp. 273-282.
Keywords. Consciousness, evolution, co-evolution, matter, continuity, discontinuity,
complexity, brain
Abstract. Theories about the evolution of consciousness relate in an intimate way to
theories about the distribution of consciousness, which range from the view that only
human beings are conscious to the view that all matter is in some sense conscious.
Broadly speaking, such theories can be classified into discontinuity theories and
continuity theories. Discontinuity theories propose that consciousness emerged only
when material forms reached a given stage of evolution, but propose different criteria
for the stage at which this occurred. Continuity theories argue that in some primal
form, consciousness always accompanies matter and as matter evolved in form and
complexity consciousness co-evolved, for example into the forms that we now
recognise in human beings. Given our limited knowledge of the necessary and
sufficient conditions for the presence of human consciousness in human brains, all
options remain open. On balance however continuity theory appears to be more
elegant than discontinuity theory.
The distribution of consciousness.
Theories about the evolution of consciousness are linked to theories about the
distribution of consciousness. Are we the only conscious beings? Or are other
animals and other living systems also conscious and, if so, might consciousness
extend to non-living systems such as computers? Philosophers and scientists have
expressed many different views on these matters. As the data needed to decide these
matters is not currently available, all views are partly speculative. Why? Because we
do not even know the necessary and sufficient conditions for consciousness in our
own brains! As John (1976) pointed out we do not know the physical and chemical
interactions involved, how big a neuronal system must be to sustain it, nor even whether
it is confined to brains. Over 30 years later, little has changed. Given this
underdetermination by the data, opinions about the distribution of consciousness have
ranged from the ultra-conservative (only humans are conscious) to the extravagantly
libertarian (everything that might possibly be construed as having consciousness does
have consciousness).
The view that only humans have consciousness has a long history in theology,
following naturally from the doctrine that only human beings have souls. Some
philosophers and scientists have elaborated this doctrine into a philosophical position.
According to Descartes only humans combine res cogitans (the stuff of
consciousness) with res extensa (material stuff). Non-human animals, which he refers
to as “brutes”, are nothing more than nonconscious machines. Lacking
consciousness, they do not have reason or language. Eccles (in Popper & Eccles,
1976) adopted a similar, dualist position - but argued that it is only through human