Here’s my version of an argument first presented by Nozick, Singer, and others: what I call the Alien Challenge.

The Greathans have come. The Greathans are a race of beings far more advanced than humans in every measurable respect. To them, the intellectual capacities of humans are roughly analogous to what we consider those of cattle to be. Greathan scientists debate over whether human communication is even complex enough to be called language. The Greathans swiftly take over Earth, and humans are rounded up and placed in pens and similar housing.

Having a taste for meat, Greathan chefs experiment with a variety of human recipes, and the new book _To Serve Man_ quickly becomes a bestseller. “Leg of Man” and “Grilled Human Breast with Mango Salsa” are favorites on Greathan cooking shows.

Unable to resist the superior Greathans with force, you and a few humans try to reason with them. Curious about your attempts to communicate, a Greathan farmer brings you before a Greathan scientist. You explain to it that you think it’s wrong for them to eat humans.

The Greathan shrugs its tentacles. “What could be wrong with it? You are not Greathan, but another species altogether. You aren’t entitled to Greathan rights. Besides, if we recognized your rights to life, what would prevent us from having to also recognize the right to life of all other earth creatures, such as dogs, pigs, and even insects or crustaceans? Plus, your claim is hypocritical: you freely eat other such creatures who you believe yourselves to be superior to, but now complain when we do the same thing to you.”

You’re taken aback by the Greathan’s reply, but thinking quickly on your feet you answer that, “look, other earth creatures don’t have language, but we do. That’s a big distinction! Surely the fact that we can talk together about these matters shows that we’re different from other creatures. We can both eat and farm these other earth creatures, but surely you shouldn’t eat us.”

The Greathan waves its tentacles idly, unimpressed. “You have a far greater opinion of your abilities than is accurate,” it responds. “You may call what you are doing using language, but we don’t. Your ‘language’ is a very primitive form of communication without telepathic content, and so is not true language. Your dogs, primates, cetaceans, and even bees do as well or better than you when it comes to communication. How we’re communicating now is for me nothing more than grunting and pointing.
“So I return to my original contention that it is perfectly right for us to eat humans and have a thriving business of farming humans, and it is hypocritical of you to say otherwise.”

The Greathan looks at you with its multiple eyes. How would you answer it?