Some Reflections on Visual Awareness

Koch 1990) that outlined a sketch of such a theory. Our aim was not to produce as complete a theory of con-sciousness as possible but to indicate promising lines of experimental work, mainly neurobiological, that might lead eventually toward a solution of the problem. We made the plausible assumption that all forms of con-sciousness (e.g., seeing, thinking, and pain) employ, at bottom, rather similar mechanisms and that if one form were understood, it would be much easier to tackle the others. We then made the personal choice of the mam-malian visual system as the most promising one for an experimental ttack. This choice means that fascinating aspects of the subject, such as volition, intentionality, and self-consciousness, to say nothing of the problem of qualia, have had to be left on one side. We have also not dwelt on unusual psychological states, such as hypnosis, dreaming, lucid dreaming, and sleepwalking, to say nothing of meditative states, since we do not see any special advantage in studying them experimentally at this stage. Our method is to combine what is known experimen-tally from both psychological nd neurobiological ex-periments with plausible theoretical arguments of a general nature. We have not so far attempted etailed computer simulations, ince it is unlikely that we under-stand the details of the system well enough for such modeling to provide decisive answers. In the long run, however, modeling is essential, and even at this stage, well-conceived computer simulations should suggest plausible general principles and thus guide the ex-perimental attack on what is obviously a system of enormous complexity and subtlety. In our previous paper (Crick and Koch 1990), we listed a number of topics and assumptions that we did not intend to discuss. This list will not be repeated here in toto except o say that we have assumed the higher mammals have a form of visual awareness fairly similar to ours, so that we can, with discretion, combine ex-perimental results on humans with those from mon-keys, cats, and so on.