At some point - we have to eat something that is alive. Even plants react to being damaged in intentional and measurable ways (including trying to repair themselves, signaling neighbors of the damage, and passing nutrients to each other in response). I think it's impossible to ditch incrementalism, because EVERYTHING we eat is already somewhere on that sliding scale of "something alive that is trying to stay that way".
I am in favor of reducing the harm I am able to, while still acknowledging that simply existing requires that I consume resources (And those resources have to be a living thing, because humans are consumers... not producers). Those resources could have gone to keep another living thing alive, but I am using them. At some point, I expect to die, and it will be something else's turn.
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Also - It would be really, really cool if we could get the whole "KloraDerm" thing going from "Old Man's War" by John Scalzi.
I would LOVE to be able to do photosynthesis.