Evolutionary radiation and the spectrum of consciousness

Evolution is littered with polyphyletic parallelism: many roads lead to functional Romes. We propose consciousness embodies one such example, and represent it here with an equivalence class structure that factors the broad realm of necessary conditions information theoretic realizations of Baars' global workspace model. The construction suggests many different physiological systems can support rapidly shifting, highly tunable, and even simultaneous temporary assemblages of interacting unconscious cognitive modules. The discovery implies various animal taxa exhibiting behaviors we broadly recognize as conscious are, in fact, expressing different forms of the same underlying phenomenon. The variety of possibilities suggests minds today may be only a small surviving fraction of ancient evolutionary radiations - bush phylogenies of consciousness pruned by selection and chance extinction. Although few traces of the radiations may be found in the fossil record, exaptations and vestiges are scattered across the living mind. (C) 2008 Elsevier Inc. All rights reserved.