The Co - Evolution of Matter and Consciousness 1

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. 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, …