From Towards a Science of Consciousness 3                                        CogNet Proceedings Module

How did consciousness evolve? Either consciousness is present in all living systems, or it emerged at some point in the evolution of life on earth. If consciousness emerged through evolution by natural selection, then either it was selected for as an adaptive feature, or it emerged as the byproduct of other adaptive features. The dominant view is that consciousness is itself an adaptive feature, playing a crucial functional role.

But this raises some crucial questions. What is the function of consciousness? What features of consciousness enhance survival beyond the abilities of increasingly intelligent but nonconscious behavior? How does consciousness exert influence on our biology? When in the course of evolution did consciousness first appear on the scene, and why? Some have argued that any function that consciousness might perform could in principle be performed without consciousness. If this were so, it would be unclear why consciousness should ever evolve. So the search for the function of consciousness is crucial to understanding the evolution of the mind.

The five chapters in this section discuss various aspects of the relationship between consciousness, evolution, and function.

Nicholas Humphrey sees consciousness as having developed from more primitive sensations which lacked subjective qualities. These arose from early organism attempts to integrate sensory inputs into an internal representation of the outside world. Eventually, through natural selection, the signals began to turn in on themselves. These generated internal feedback, formed multiple representations and ultimately "privatized" sensations. Humphrey suggests that within self-sustaining inward loops, the subjective qualities of consciousness played a crucial role in the perception of time.

Richard Gregory builds on this suggestion of Humphrey, stressing that qualia are useful to "flag" the present moment. Gregory points out that increasingly complex organisms developed a need to identify representations of the present, as opposed to past memory and future anticipation. How does the mind know when is now? By adorning representations of the present with consciousness qualia, Gregory suggests. Gregory connects the "now" with modern philosophy, cognitive science and physicsæa connection worthy of intense pursuit.

But what are qualia? Can they be described within science? Did they evolve and are they describable by physico-chemical systems? Graham Cairns-Smith argues that, yes, qualia belong in our science and their mystery will be solved. He notes that qualia must play a function to evolve, which implies that they must have a physical bases. He suggests that qualia are generated by biomolecular systems ("qualogens") whose diversified phylogeny matches that of the qualia themselves. He suggests that their underlying nature may be quantum-mechanical: feelings and sensations are associated with vast numbers of microscopic processes bound in some type of macroscopic quantum state.

Leaving aside for the moment the original onset of primitive qualia and consciousness, archaeologist Steven Mithen examines the fossil record to try and pin down the onset of the type of complex, higher order consciousness with which we are familiar. This type of consciousness, Mithen observes, must surely have grown from interactions among thought, language, behavior and material culture. He traces the course of human evolution in the 6 million years since humans and apes diverged. Mithen focuses on the construction of handaxes by several types of early humans which first appeared in the fossil record 1.4 million years ago. He argues that their construction required not only sensory-motor control and an understanding of fracture dynamics, but also a desire for symmetry, an ability to plan ahead, and internal (unspoken) language. Toolmaking flowed into art and agriculture some 50,000 years ago, representing, Mithen concludes, the "budding and flowering" of human consciousness.

Like Mithen, neuroscientist   William H. Calvin is concerned with higher levels of consciousness, seeing them as the top rungs in a hierarchical series of a dozen-or-so levels. Percolating upward through this hierarchy, Calvin explains, are the substrates for ideas, actions and sensations which emerge into consciousness by winning a competition with other possible ideas, actions, or sensations. Consciousness is the result of a Darwinian processænot only over the course of evolutionæbut in a moment-by-moment competition for a place in the sunshine of awareness. In Calvin's view evolution is the fundamental process, applicable over various time scales and in systems of all sorts.