Imagine some aliens descend on earth looking for intelligent life; the self-dubbed homo sapiens proves disappointing in that regard, but we turn out to be tasty.
Imagine the aliens have such cognitive sophistication that they can hold thousands of simultaneous conversations at rates thousands of times faster than the fastest human speech, never losing their places. From their vantage point, all of human behavior – anything we might do or say – is predictable and boring, and yet they adore the succulence of our flesh.
We can’t converse with them, since we can’t formulate thoughts that match the complexity of even their most vacuous chit-chat, and yet they do understand our own grunts and gesticulations – in fact, they can anticipate these grunts with stunning precision. To them we are robots acting on a discernible program. We might proudly present the greatest achievements of our science, our literature, our music, and to them it all seems as insect architecture might seem to us.
These aliens notice how we pollute our habitat, how we slaughter and enslave our peers, and how we eat other animals we deem inferior and expendable. How then could we persuade the aliens that while we can be ground into delicious burgers we should rather be allowed to live, even to be recognized as members of their moral community?
If we had no hope of befriending them as equals, and if we could offer them nothing new in the domain of information, perhaps our best argument would simply be that we’re alive, that we feel pain, that in our capacity to suffer, we are like them. But that’s not a logical argument, it’s an appeal to empathy, and how could we expect these aliens to relate to creatures as primitive as we are, particularly when the aliens are hungry and the smell of our flesh on the grill makes such a persuasive case against compassion and for exploitation. How – tell me – how could a human persuade a peckish alien taxonomist not to classify all humanity as a resource to be tapped for nutrition and enjoyment?
I suppose we might still carry out the hope that empathy – as a phenomenon – can extend across species and types of mind and can be entertained even on an empty stomach. Our treatment of other animals on earth is an opportunity to affirm or destroy that hope, no matter whether the aliens here discussed are mere figments of a thought experiment.
Rudi Seitz 
I understand you’ve prepared the elements to fulfill the thought experiment which I enjoyed. I wanted to arbitrarily go on a tangent — perhaps to your annoyance though. I really like Michio Kaku’s idea of class 0 – 3 civilizations. Here’s a youtube video where Michio discusses his theory in detail: https://www.youtube.com/watch?v=JdILmgJGuvw
I really like his analogy with respect to aliens (perhaps in another video) that have gained the ability to travel to different stars or galaxies. I’m paraphrasing his idea but here it is. An advanced civilization with such technology would be akin to us driving our cars on the highway and on the side of that highway a small ant hill resides. We might notice the ant hill or not. Even if we did notice it, we probably wouldn’t pull over on the shoulder to take a look. The drivers of the cars would represent the advanced alien speeding past earth. Yes, they could obviously come steal our resources, eat us, exterminate us, etc., however, whatever pleasure, resources, or otherwise they might receive from earth, they would already be capable of producing on their own at levels beyond our comprehension. It may be naive to think this but, assuming these sentient beings were similar to us and experienced pleasure as we do. I believe that aliens with the technology to travel to distant stars would also have the technology to produce or manipulate matter in such a way as to create whatever substance they desired in whatever quantities they needed — very similar to Star Trek’s replicator. Even if they could not yet convert energy into matter they would surely have the capability of mining everything they needed from an endless supply of lifeless bodies such as asteroids, planetoids, nebulas, or maybe even stars themselves. Whatever pleasure they might derive from eating earthlings would be something they could easily reproduce physically or mentally on their own. Not only could they reproduce that pleasure, but they could customize and tweak it to their own individual subjective needs bringing that experience so far beyond whatever they would experience if they did it for real. Earth would be an insignificant spec in a relative infinite pool of free floating resources. I think if we ever do get invaded by aliens hoping to take our resources, that it would happen very quickly. We’d either all be exterminated in the blink of an eye or whatever fully automated, remotely controlled, or even inhabited mining ship(s) would be incredibly efficient and gather all the resources it desired at an incomprehensible speed, perhaps in a day or less after which all humans would quickly die as a result. We would not have the chance of seeing them gather in the skies, while we send fighter pilots to investigate or attack them. And even if we did, we might just barely get their attention if only by amusement as our missiles would feel like small bugs hitting the windshield of a car.
Ultimately — and I know I’m not saying anything new — we should be most concerned with the humans on this planet who already have the power to exterminate all humans. Blowing ourselves up is so much more probable than aliens doing it. I hope we’re smart enough to survive our own stupidity.
Scott
Thanks for your comment! I agree, it’s improbable that a civilization could be advanced enough to travel to earth from afar, but primitive enough that they’d need to satisfy themselves by eating earthlings. As you mentioned though, this post is a thought experiment. It’s not really about aliens per se; they’re just used here to aid us in exploring our own attitudes towards (non-human) animals on earth, by putting us in the animals’ position.