"Rupert" > wrote

> Yes, you're right that it is highly controversial, and I never
> suggested otherwise, but he confirmed my belief that the majority
> opinion of ethicists is that different amounts of consideration based
> on species is something that needs to be justified, the burden of
> proof is on the speciesist.

The consideration differences that exist in so-called "speciesism" are not
actually based on species. One thought experiment to illustrate would be to
imagine that a friendly extraterrestrial race of beings arrived on earth
that had superior intellectual capacities to humans. That species would
automatically be given full consideration equal to humans, and it would not
be based on species, it would be based on the totality of the entire
constellation of capacities inherent *in* the species. The reason that other
"isms" like racism and sexism are wrong is that they are based on
misconceptions about the capacities of the groups they discriminate against.
The discrimination we have against sea sponges is not based on a
misconception.

There's your proof, and explanation.