COMMENTARY On Being Importantly Necessary for Consciousness

Engel et al. (1999) claim that ‘‘appropriate synchronization among cortical neurons may be one of the necessary conditions for the buildup of perceptual states and aware-ness of sensory stimuli.’ ’ The question I wish to examine in this brief comment is exactly what they mean by a ‘‘necessary condition’ ’ for consciousness. For example, gravity is surely necessary for human consciousness, for without gravity life itself would not be possible. On the other hand, when singling out the items of study for consciousness in the brain, gravity does not rank high on the list of possible suspects since there are other things also necessary that somehow seem closer to being suffi-cient for consciousness as well. I want to examine where on the continuum of items of interest for the study of consciousness neuronal synchronization is likely to rank: Does it resemble gravity or does it resemble substance(s) C, the sufficient factor(s)? Let me put my query another way. When we devise scientific theories to explain phenomena in the world, we single out some causal relations among the vast web of interactions as the important connections for understanding some event. Some causal influences are too trivial to matter much in a general theory; others are to