Can animals and machines be persons?

"This is a dialogue about the notion of a person, of an entity that thinks and feels and acts, that counts and is accountable. Equivalently, it's about the intentional idiom -- the well-knit fabric of terms that we use to characterize persons. Human beings are usually persons (a brain-dead human might be considered a human but not a person). However, there may be persons, in various senses, that are not human beings. Much recent discussion has focused on hypothetical computer-robots and on actual nonhuman great apes. The discussion here is naturalistic, which is to say that count and accountability are, at least initially, presumed to be naturally well-knit with the possession of a cognitive and affective life." -- Justin Leiber, from the Introduction