To what extent would we be justified in placing a non-human animal at the same level of moral standing as the humans who share its mental capacities? Would it be appropriate, for example, to think orangutans have the same moral rights as near-persons who have similar planning skills and emotional capacities? Or is this anthropomorphic temptation to ignore species boundaries a deep mistake scientifically and philosophically? A mistake with potentially profoundly dangerous ethical consequences for how we treat the mentally unfortunate among us?

To answer these questions we must know more about animal consciousness and the argument from analogy that must be used to confer moral status on nonhumans. There are many problems here, from establishing which animals, if any, are conscious to deciding what moral implications, if any, consciousness has.

In succeeding modules we will consider the psychological capacities of four different classes of chordates: nonhuman mammals, birds, reptiles, and amphibians. The reason we choose vertebrates is that the case for animal consciousness seems prima facie more plausible in their case than it does for species lacking brains, spinal chords, and central nervous systems. But first, read Colin Allen's fine survey of the issues in the Stanford Encyclopedia of Philosophy.