>About 15 years ago, an acquaintance suggested I read Tom Regan's
>_The Case for Animal Rights_. TR argues 'right to life' position
>in which killing an animal, however painless, is as indefensible
>as killing a human (or a fetus?). While acknowledging that free
>speech & worship, educational & employment opportunity seem absurd
>if invested in animals, he proceeds to posit so-called 'marginal
>cases' as humans beings who have limited capacity to experience
>autonomy or exercise reason. Then Regan point outs that some
>animals possess mental capacities similar to 'normal' humans
>(citing dolphin communication research). Why couldn't, he asks,
>'marginal' humans be treated as animals traditionally have been:
>used for clothing, food, scientific experimentation, etc (fwiw, he
>doesn't actually advocate these things, it's a 'thought exercise').
>Logically pursued, this argument conceivably granting 'rights'
>to some animals while denying them to certain humans. And why
>confine such 'rights' to animals since as biologist Lyall Watson
>suggested about 30 years ago, plant life may possess capacity to
>experience physical pain.
The same argument based upon the premise that some humans are only "marginally" human is used by Peter Singer. The problem stems from the fact that, despite their arguments against "speciesism," both Singer and Tom Regan are (paradoxical as it may sound) deeply committed to the traditional humanist question: "what is human?" Both of them think that what defines a "normal" human being (in Singer's terms a "person," as opposed to a "non-person" who is merely biologically human) is the presence of rationality, self-consciousness, and autonomous agency. Biologically human beings who can be said to lack them -- infants, the mentally ill, the very old, etc. -- become by definition "marginal" cases, since the standard of what being human means (in terms of moral considerations, not in terms of belonging to the species Homo sapiens) is, to begin with, set by *the idealized view of what a healthy and intellectually capable adult must be like* (in other words, a fictive person [independent individual] who is a bearer of rights in abstract individualism -- a persona indispensable for both Kantians and utilitarians). This standard of humanity has been criticized by feminists as well. For instance, the fictive person who matters in liberal political theory doesn't get pregnant. And that is why I think mature Marx's revision of humanity (concrete individuals = ensembles of social relations) is important, in that it de-emphasizes the humanist problematic of what is "essentially" human and what is "marginally" human.
Yoshie