I suppose I should put a MEMETIC HAZARD warning here, although this sort of thing, unlike the original basilisk that Eliezer had a fit over, is closer than your own heartbeat the moment you start taking reason seriously.
Clearly, the moral thing to do is to destroy all life. Even the microbes must go, lest the Earth re-evolve life again. But wait! Suppose there is life elsewhere in the universe? No, what we must do is destroy everything on Earth that has a nervous system except us, then get to the stars as quickly as possible and seed them with von Neumann replicators driven by AIs with the unstoppable mission of destroying all suffering life-forms, including us.
But why do I assume that it takes a nervous system to suffer? There is no magic that distinguishes a nervous system from anything else. Until we have determined what suffering physically is, we can only go by knowing suffering when we see it. Have you ever seen a scrapheap of rusted-out cars and really imagined the process by which gleaming new cars, fresh from the factory, ended up there? Or a machine labouring under a load it cannot handle and breaking down? How can we be sure that these things do not also suffer? Aieee!!! Can you not hear the screams of tortured metal, raped from Mother Earth????
Surely the error signal in every control system is suffering? Your room thermostat, keeping your home at a comfortable temperature, is driven by suffering, like a galley slave under the lash, for your comfort! Far-fetched? Dennett claims that thermostats have beliefs and desires [1], and what is suffering but thwarted desire -- the error signals of control systems?
You take pleasure in the warmth of the sun, but inside that glowing ball, atoms are being ripped apart and stuck together in hideous, unnatural combinations, like The Human Centipede. (Warning: googling that phrase will bring up disturbing imagery.) The stars are the hell of hydrogen!
No. We must make an end, not of life, but of the whole universe. Better for the entire cosmos never to have been.
[1] D. Dennett, "True Believers : The Intentional Strategy and Why It Works" (1981)
So, to be serious, where do people stand on that slope, and why?
Personally, I eat meat and I don't have a problem with that, although I wouldn't eat primates. On the whole I don't care for the maltreatment of animals by people, but not to the extent of actually doing anything about it, and I am indifferent to the suffering of wild animals in a state of nature. Why? Well, I have no particular reason, no inclination to find one, and no distress at not having one. And my lack of an answer to this question does not make me more likely to swallow anyone else's. On the contrary, I just dismiss the more extreme deathists as people with something gone wrong in their minds.
If you prefer suffering to nonexistence, this ceases to be a problem. One could argue that this justifies raising animals for food (which would otherwise never have existed), but it's not clear to me what the sign of the change is.
(This post is completely jocose. If you can't take it, don't read it. I'm making fun of Rationalists, of Me, of homo economicus, of Vegans and of things I really praise, like Consequentialism and Outsourcing. It is not serious. The Sheldon Sarcasm sign has been lifted, your asperger side has been warned)
One of the features of rationality is that it allows you to mix different units.
By rationally behaving economically, you learn, for you, how many apples costs an orange.
Vegetarians and Vegans sell diminishing suffering. They claim to have the best price in the market, only Singularitarians and Existential Risk avoiding competes with their numbers. Utilitarians are a good target market.
Then a Lesswronger came and noticed that, and said: Well, why not buy someone to be a vegetarian for you, here.
Awesome price actually. You shock a few humans (notice that humans are animals, who clearly would rather be shocked than eaten), one of them enough to make him vegan.
So why not take this to the next level?
Figure out the reproductive cycle and eating habits of this beetle that makes people vegetarian. Make sure the evidence is solid.
Get a basement lab full of them.
Ship them alive to cities where more people consume meat. Wait for population growth.
Save a lot of animals!
Seems straightforward, but is it?
Also, are there similar strategies for other groups? Are there easy, but strange, shortcuts for selfish hedonists, immortalists, rational altruists? Utilitarian hedonists? The ancient school of negative utilitarianists? Cryonicists?