Although I'm not convinced that sparing spiders is justified on self-interested grounds (aren't most prey insects less dangerous to have around than spiders? if you introduce new spiders, yes, they will starve, but wouldn't this still cut the prey population at least in the short term?), you make good points on that front, and more important, you are right that, even if someone's reasoning is shaky, it is unfounded for me to assume a specific motive without evidence for that motive.
A common trope when it comes to predatory arthropods is, e.g., "Don't kill spiders; they're good to have around because they eat other bugs."[1] But, setting aside the welfare of the beings that get eaten, surely this is not people's true objection. Surely this reasoning fails a reversal test: few people would say "Centipedes are good to have around... therefore I'm going to order a box of them and release them into my house."[2] What is implied by the fact that non-EA people are willing to spare bugs based on reasoning that is, by their own lights, thin? I think it indicates that many (most?) people have some instinctive empathy even for arthropods and when they are given the choice to kill one, they will look for reasons to avoid it. So, while I think there may be better reasons to avoid killing bugs, their reasons may be a positive sign that people can be persuaded to be more pro-animal when animal suffering is made salient to them.
"While nobody likes creepy crawlies running around their home, these centipedes are actually on the lookout for even nastier pests [...], including cockroaches, termites, spiders, and silverfish."
This post is not intended to be for or against squashing centipedes or spiders; I don't have a strong take on that topic.
If you only care about reducing the total amount of bugs in your house and not about the welfare of those bugs, surely the optimal thing to do is to squash the centipedes and then also do things to prevent other bugs.
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Your point applies to your second and third hypotheticals, since there is no reason to believe x is better than not-x. But surely the mugger is more likely than the anti-mugger since you are talking to the mugger whereas the anti-mugger is just a hypothetical.
Although I'm not convinced that sparing spiders is justified on self-interested grounds (aren't most prey insects less dangerous to have around than spiders? if you introduce new spiders, yes, they will starve, but wouldn't this still cut the prey population at least in the short term?), you make good points on that front, and more important, you are right that, even if someone's reasoning is shaky, it is unfounded for me to assume a specific motive without evidence for that motive.
Yeah good point. Not a great reason either, but arguably an equally plausible psychoanalysis.
On sparing predatory bugs.
A common trope when it comes to predatory arthropods is, e.g., "Don't kill spiders; they're good to have around because they eat other bugs."[1] But, setting aside the welfare of the beings that get eaten, surely this is not people's true objection. Surely this reasoning fails a reversal test: few people would say "Centipedes are good to have around... therefore I'm going to order a box of them and release them into my house."[2] What is implied by the fact that non-EA people are willing to spare bugs based on reasoning that is, by their own lights, thin? I think it indicates that many (most?) people have some instinctive empathy even for arthropods and when they are given the choice to kill one, they will look for reasons to avoid it. So, while I think there may be better reasons to avoid killing bugs, their reasons may be a positive sign that people can be persuaded to be more pro-animal when animal suffering is made salient to them.
For example: an article titled "Why you should never squash a house centipede" states:
This post is not intended to be for or against squashing centipedes or spiders; I don't have a strong take on that topic.
If you only care about reducing the total amount of bugs in your house and not about the welfare of those bugs, surely the optimal thing to do is to squash the centipedes and then also do things to prevent other bugs.
Your point applies to your second and third hypotheticals, since there is no reason to believe x is better than not-x. But surely the mugger is more likely than the anti-mugger since you are talking to the mugger whereas the anti-mugger is just a hypothetical.