What a thoughtful comment--but then, you are @litguru :)
if all organisms have sentience, then should we stop killing them all
I think we can start by being thoughtful when we kill. By that I mean, it should cost us when we take a life. I believe (my philosophical,ethical perspective--not scientific) that all life is related. When we start creating hierarchies based on ability or utility, then what are we really saying? Does a disabled person without measurable cognitive skills have less value than someone with superior intellectual ability? Is the serf worth less than the lord? Do we value the suffering of one over the other?
Jainism came to mind when I wrote this. It's all very difficult and I have no answers except for this: If we insist that is is necessary to kill, then we need to be aware that we are taking life, that we are making a choice. Even when we use resources, cut plants in order to provide for ourselves, be aware, be judicious and respectful.
Animal experimentation certainly comes to mind. How many guinea pigs and frogs have been sacrificed in high school science classrooms when that information can as easily be obtained from a textbook? I tested this once: told the college bio lab teacher I didn't want to dissect an animal. She told me OK, as long as I could pass the test, which was to identify organs in a dissected pig. I studied diagrams and passed with flying colors. Think of all the pigs that were wasted that year, in that one class. Think of all the wasted life, all the suffering inflicted on animals in all the laboratories, for no real purpose.
Well I did go on, didn't I? Sorry....
Thanks for stopping by, @litguru and commenting.
It is definately a complex problem. Maybe 3D printed meat will save the day.
As an anecdote, I was on a trip to Spain once, when I saw a documentary on octopus intelligence. That same day, I went out to a place where everyone was drinking wine and eating octopus. That's the tradition there. Imagine me surrounded by all those happy people drinking and eating octopus. Had I not watched that documentary, I would have partaken of the octopus party. As it happened, I did not. I still regret it in my weak moments, but to this day I have not touched another octopus. :)