Consciousness

There are many scientific and philosophical problems concerning consciousness, but in 1995 David Chalmers proposed using �the Hard Problem� to refer to the principal scientific problem of consciousness, which is to understand how physical processes in the brain relate to subjective experience, to the feeling of being someone. As he put it, �It is widely agreed that experience arises from a physical basis, but we have no good explanation of why and how it so arises� (1995). Unfortunately, the scientific investigation of experience is impeded by the unique epistemological status of consciousness, for while scientific observation is based on specific experiences, consciousness is the ground of all possible experience (MacLennan, 1995). Chalmers called on researchers to face up to the Hard Problem, and Shear (1997) collects a number of papers responding to his challenge.

Of course, neither Chalmers nor I intend to suggest that all the other problems connected with consciousness are �easy�; indeed, some of them are as difficult as any in neuropsychology. However, they may be approached using ordinary scientific methodology, as developed in cognitive science and neuroscience, and so in this sense they are �less hard� than the Hard Problem. They have in common that, at least in principle, they can be solved in terms of neural information processing and control, without reference to any associated subjective experience. In this article I will begin by considering some of these �less hard� problems, especially in the context of robot consciousness, which provides a useful point of contrast and comparison to these problems in the context of humans and other animals. Then I turn to the Hard Problem in the contexts of both natural and artificial intelligence.