During and after rainstorms in the spring time, I encounter many dozens of worms washed up on the sidewalks. Some of them look healthy as they vigorously wiggle their way along the pavement, but many others appear helplessly trapped and unable to move. I often wonder whether it would be merciful to quickly squash the latter worms, in order to hasten an otherwise protracted death.

Out of selfishness, I would prefer the answer to be "No, it doesn't prevent suffering to squash the worms instead of leaving them to die," because this would exempt me from compunction about not spending more time to help them. However, I'm curious to hear an honest answer. If worms can suffer meaningfully (my probability is > 0.2 that they can), and if quickly squashing a dying worm would prevent several minutes or hours of severe pain, then I could directly prevent a fair amount of suffering by spending some time walking around to kill them.

A small proportion of the dying worms are actively thrashing about, and these seem fairly obviously to be in pain (if worms can indeed feel pain of the type we care about). But most lie relatively still, seemingly unable to finish a journey across the pavement that they tried to begin. However, they seem to have enough hours of life left in them that I would guess that squishing them is less agonizing than letting them remain as they are.

To quote Jeff Lockwood from the comments of my earlier blog post on this subject:

I’d concur that it is ethically sound to kill a partially crushed worm (there is even some biochemical evidence that worms can suffer, as they possess serotonin and endorphins). They writhe and appear to exhibit behaviors that a compassionate and reasonable person would justifiably conclude are evidence of suffering (the issue being—if you are wrong and the worms aren’t suffering, then nothing has been lost by your action, other than a moment of time and the angst of mistaken empathy, but if you are right, then those who don’t take a second to act compassionately lose a great deal as does the worm). My sense is that it takes a rather long time for a partially crushed worm to die, as its physiology and anatomy are such that death would not follow nearly as quickly as it would for a mammal with a more complex and concentrated set of vital organs.

Because I don't enjoy the process of spending time to crush worms, I would be grateful to discover that they're better off being left alone; but I doubt this is the case. I wonder: Is there a more systematic method that people could use to prevent worms from suffering like this?

Thanks for the comments!

Other things being equal, a sentient being whose life has irreversibly fallen below hedonic zero should be swiftly euthanased IMO. But the "other things being equal" condition clearly carries a lot of weight here. Thus how does one guard against the coarsening and brutalizing effect of killing, which may spill over into other areas? In the case of dying worms, I'm not clear there is a unitary subject who is in agony, as distinct from individual ganglia each undergoing discrete pains. This observation isn't intended to trivialize invertebrate suffering, just to indicate why I think a principled case can be made for our prioritizing the plight of vertebrates with a central nervous system - a plight that coincidentally is more accessible to intervention with existing technologies.

More generally, I think the only way to make a significant impact on wild animal suffering is to tackle the problem systematically - i.e. via compassionate ecosystem redesign, cross-species fertility control, global GPS tracking and surveillance, neuro-implants, population management etc - rather than piecemeal initiative. And the biggest obstacles here will be ideological not technical.

a unitary subject who is in agony

I think that's a nice way to phrase what we mean when we say "an organism feels pain in an ethically relevant way." It seems an open question whether that applies to worms. Thanks for the reply, Dave!

It is sometimes observed that one withdraws e.g. one's hand from a hot stove before one actually experiences the phenomenal pain. This might seem to show, trivially, that [the neurophysiological substrates of] phenomenal pain didn't cause one's hand to withdraw. But this inference is too quick. Maybe peripheral nervous system ganglia did experience phenomenal pain, but one's CNS had no access to that pain, merely its causal effects. On this conjecture, there are (at least) two pains; the extra-cranial original and - after subsequent neurotransmission - the sharp pain in one's CNS a hundred or so milliseconds later - which one locates in [the somatosensory representation of] one's hand.

On this story, do some of one's peripheral nerve ganglia therefore potentially have independent moral status? If one is a utilitarian, ultimately yes - but presumably an attenuated moral status because such "encapsulated" raw pains lack the complex spectrum of affective experience that accompanies raw pain as experienced in the CNS.

Anyhow, assume for the sake of argument that something like the above conjecture is true. Are, for example, the nerve ganglia in each of the segments of segmented worms potentially objects of moral concern? A severed octopus arm? ( http://news.bbc.co.uk/1/hi/england/nort ... 498291.stm ) How about the detached tail segment of an injured lizard ( http://www.youtube.com/watch?v=qIQi-OSU1VE ) and not just the injured lizard himself?

I suspect some readers will find such speculations fanciful and/or ethically trivial compared to our other priorities. Maybe so. But within the next century or so we'll have the capacity computationally to monitor and micromanage every cubic metre of the planet in exquisite detail. And if we're serious about getting rid of unpleasant experience altogether, the option will be available - and well worth planning in advance.

My position is actually more conservative. I think I only care about the awareness of the pain by the CNS, not the peripheral nervous response. For instance, I don't care if my body has nociceptive reactions when I'm under general anaesthesia -- I just care that I'm not consciously suffering. Still, it's to me unclear whether worms and other invertebrates might have some sort of conscious awareness of pain.

Alan Dawrst wrote:a unitary subject who is in agony

I think that's a nice way to phrase what we mean when we say "an organism feels pain in an ethically relevant way."

Is it? The way Dave himself used it doesn't sound that ethically relevant to me - qualia-experiencing ganglia seem as relevant as suffering unitary consciousnesses to me. 'Can they suffer?' and all that...

I'll second some of the comments made so far. Firstly, it seems greater than a 10% chance that worms can suffer. It's hard to say what the magnitude of the suffering is, or who it's experienced by. As Arepo says, only the magnitude of the suffering matters, not whether it's integrated into a whole, as David suggested. Now should we euthanase worms whose lives are worse than a life not lived at all? All other things being equal, yes. But all other things are not equal. A campaign for euthanasia of worms would be met with riducule. It's decades ahead of its time, at best. And being decades ahead of your time, although retrospectively prestigious, is not constructive! What's needed is people who will be five to ten years ahead of their time. We need people to actually make a difference to the compassion of our society, and that's not going to happen by promoting the squashing of worms. If I've given off an air of ridicule, well I can explain. The idea that squashing worms is helpful is greatly out of touch with society. That is, it is ridiculous. It may yet be true. But what it will not be, is constructive. It's not something we can go around telling non-utilitarians.

Hope that's a helpful perspective.

RyanCarey, thanks for that reply. You make an excellent point that it would be less than optimal to promote this particular cause now, since it's too inferentially distant for most people.

Still, I struggle with the question of whether I should feel sorry about not spending an extra few minutes to kill the worms myself in private. If I could euthanize them entirely painlessly, squashing would be unambiguously a good idea. But in practice, squashing probably involves some pain, and I can't tell if the worms would actually suffer less if I left them to die on their own.

So I would speculate that pain is present because it teaches us to avoid something. When we touch a flame, we feel our hands being burnt and we withdraw them. Similarly, the sensation of drownin gdiscourages us from staying underwater. Pain seems to be put their by evolution. It discourages us from damaging our tissues, so that they will remain and allow us to survive, and later reproduce. Note that a kick in the groin is an event that is evolutionarily not supposed to happen. So the question is, how can you outsmart evolution? Drowning will hurt. Squashing will hurt. Carbon monoxide poisoning will not hurt. Evolution doesn't anticipate that sort of death because worms don't encounter carbon monoxide poisoning in nature and even if they did, they wouldn't be able to avoid it. So my speculation leads us to the point that if you want to really reduce pain, you need to kill the worms in a way that does not resemble a natural death of a worm, and that could not naturally be avoided by a worm.

Nice point. Of course, many non-natural ways of dying do entail pain as a byproduct (due to tissue damage, etc.), but some don't. Research on humane methods of killing is very valuable, both for worms and other animals.

Of course, many non-natural ways of dying do entail pain as a byproduct (due to tissue damage, etc.)

Yes, exactly. That's a tricky part.

Here are my updated thoughts on this topic. Originally, I leaned toward thinking it would be more humane to squish worms and put them out of their misery. However, now I'm less sure. The pain of a whole-body squishing could be extremely intense even if it only lasts a second. It basically involves turning on tissue-damage nerves all over the worm's body. Leaving the worm to die means that it will endure many hours of slow internal-organ failure or dehydration, but maybe this would be preferable because only a few organs have to fail to produce death? One doesn't need to squish the whole thing and destroy every part of the worm to kill it. I've also read that dehydration can be one of the more humane ways for humans to die.

An alternate idea could be just to sever the worm's head. Worms have cerebral ganglia at the front of their heads, and if worms are conscious at all, I would guess this part is (solely?) responsible. From one article:

The cerebral ganglion, located at the front of the worm, serves as the brain. This nerve bundle is responsible for receiving external information such as light, heat, moisture and vibrations. The worm relies on the ganglion and a ventral nerve cord for sensory input from the world around them.

So an alternate idea could be to cut off the worm's head. [EDIT: I'm not sure this would actually be a good idea, because invertebrates have more distributed nervous systems than vertebrates, so it's possible non-head parts of the worm are conscious too....]

But unconsciousness might not be immediate here. I don't know how worms differ, but for humans:

The current medical consensus is that life does survive [after the guillotine], for a period of roughly thirteen seconds, varying slightly depending on the victim's build, health and the immediate circumstances of the decapitation. The simple act of removing a head from a body is not what kills the brain, rather, it is the lack of oxygen and other important chemicals provided in the bloodstream. To quote Dr. Ron Wright "The 13 seconds is the amount of high energy phosphates that the cytochromes in the brain have to keep going without new oxygen and glucose" (Cited from urbanlegends.com, no longer extant). The precise post-execution lifespan will depend on how much oxygen, and other chemicals, were in the brain at the point of decapitation; however, eyes could certainly move and blink.

Do You Remain Aware?:
This solely technical survival forms only part of the answer; the second question is 'how long does the victim remain aware?' While the brain remains chemically alive, consciousness can cease immediately, caused by the loss of blood pressure or if the victim is knocked unconscious by the force of the decapitating blow. If that weren't to happen immediately, an individual could in theory remain self-aware for part of the thirteen-second period. There is no consistency in this answer, as the precise length of both actual, and practical, survival will vary depending on the victim. Of course, this applies to many forms of swift decapitation, and not just to the victims of the guillotine.

Another source gives a similar estimate:

Dr. Fink believed the brain might remain conscious as long as 15 seconds; that's how long cardiac arrest victims last before blacking out. (Dr. Fink's colleague put the window of awareness at 5 seconds.)

It goes on to describe an eyewitness testimony explaining how a person saw his friend display "first of shock or confusion, followed by terror or grief" after decapitation.

Would it be any better to squish the head rather than just severing it? Presumably this would induce unconsciousness faster. OTOH, it would destroy more tissue and so might be more painful for a fleeting fraction of a second?

You would also want to make sure you got the head and not the tail. It wouldn't be cool to go around squishing worm tails while leaving the head intact.

Lots of interesting questions to ponder. If I had to guess now, I would give this ranking for humaneness of deaths:

leave alone ~= squish head > sever head ~= squish whole body

What do you think?

Brian Tomasik wrote:I've also read that dehydration can be one of the more humane ways for humans to die.

The question is, compared to what. I would prefer instant crushing of my skull over dehydration.

As for awareness, awareness of strong damage doesn't necessarily imply agony. I've seen footage of people who were cut in half at gut level. They were conscious, talking but didn't show signs of strong pain.

As for worms, how many will you squish in your life? Probably not many. When I have to get rid of spiders I try to squish them suddenly and completely.

Hedonic Treader wrote:I would prefer instant crushing of my skull over dehydration.

Interesting. I think I might prefer dehydration, though I'd like to learn more about it. The split second of crushing might outweigh several days of thirst, exhaustion, fatigue, and loss of consciousness.

Hedonic Treader wrote:As for awareness, awareness of strong damage doesn't necessarily imply agony. I've seen footage of people who were cut in half at gut level. They were conscious, talking but didn't show signs of strong pain.

True. Sometimes there is agony, and sometimes there isn't. Worms do writhe a lot when incompletely squished, and of course that's not proof of suffering, but if they can suffer at all, it makes it more likely that squishing causes suffering.

Hedonic Treader wrote:As for worms, how many will you squish in your life? Probably not many.

During the spring season, there are many days when the sidewalk is littered with worms. So it's fair to say I could squish hundreds of them per year if I thought doing so was for the best.