Preventing the most animal suffering

• The Moral weight of an organism is lifespan multiplied by total capacity for welfare.
• Welfare ranges are expressed as a percentage of the human range, which allows you to compare interventions that help humans versus ones that help animals
• Love how Bob Fisher is a philosopher but he's also very practical. Like "oh what proxies can we measure for welfare?"
• The capacity for welfare for a chicken is about a third of humans
  • This seems weird, but actually why would we expect chickens to have an order of magnitude different pain experience than animals that have very similar brains? especially as the pain system is very evolutionarily old
  • If you think a third is wrong, what do you think the number is? I suspect people don't have any answer, and if you force them to define an answer, they would be left with an uncomfortable conclusion
• Some animals may actually have a greater welfare range than capacity for welfare than humans. For example it's possible that simpler animals need stronger pain signals to get them to do stuff, which would mean that insects might feel pain more intensely than humans do.
• Insects used to be huge in the dinosaur era and although they've evolved to be smaller, it's not clear to me that they would have evolved to lose all of their capabilities as they got smaller. So they might still have the capabilities of organisms that are much larger than them. if we bred humans to be smaller and smaller until they were about say three feet tall on average, do you think that they would lose their consciousness.

Rethink's approach

• Our objective: provide “moral weights” for 11 farmed species.
• To make this tractable, we made four assumptions: utilitarianism, hedonism, valence symmetry, and unitarianism.
• Given these assumptions, an animal’s “moral weight” is that animal’s capacity for welfare—the total amount of welfare that the animal could realize.
• Capacity for welfare = welfare range (the difference between the best and worst welfare states the individual can realize at a time) × lifespan.
• Given welfare ranges, we can convert welfare improvements into DALY-equivalents averted, making cross-species cost-effectiveness analyses possible.

https://rethinkpriorities.org/publications/an-introduction-to-the-moral-weight-project