  The functional or Why question asks about the value or role or consciousness and thus indirectly about its origin. Does it have a function, and if so what is it? Does it make a difference to the operation of systems in which it is present, and if so why and how? If consciousness exists as a complex feature of biological systems, then its adaptive value is likely relevant to explaining its evolutionary origin, though of course its present function, if it has one, need not be the same as that it may have had when it first arose. Adaptive functions often change over biological time. Questions about the value of consciousness also have a moral dimension in at least two ways. We are inclined to regard an organism's moral status as at least partly determined by the nature and extent to which it is conscious, and conscious states, especially conscious affective states such as pleasures and pains, play a major role in many of the accounts of value that underlie moral theory (Singer 1975).