Owning cats is not vegan

[brimstoneSalad]

Now, obviously, people can and do get addicted to opioids whether or not they feel pain, and the same may be happening in fish.

That's what the control is for.

nor do they have neuroanatomical structures needed for that.

What gives you that impression?

People with congenital insensitivity to pain have a low proportion of the group C nerve fibres, and fish either have a lot lower proportion or none at all.

In humans that may be predictive. No good reason to assume so of fish. There are plenty of cases where one mechanism is repurposed for something else.
What we *know* is needed for pain, nerves and a brain to interpret those signals, is present. The rest is a rather poor case of induction.

We know fish experience irritation, such as from parasites (you might imagine it as an itching feeling) since they'll respond to such stimuli by scraping the area on rocks and things in the environment.

It's possible they don't experience chronic pain (as I explained), but it's very unlikely they don't experience pain at all since it's something necessary to navigate even a marine environment and avoid tearing yourself up on sharp rocks, coral, etc. Particularly if they're using those rocks to scrape off parasites: there has to be a sensation that tells them when to stop scraping because they're doing damage. Children with congenital insensitivity to pain tend to self harm if not well restrained, chewing off fingers, gouging out eyes, etc. A sensation (some form of pain) that prevents that is essential to any complex motile organism.
Any speculation appealing to neuroanatomy to say even acute pain is unlikely just ends up debunking its own assumptions.

Or maybe you are just rationalizing that somebody who disagrees with you on so many issues has to be mentally ill?

No, that's an issue independent of any of this.

[Red]

Is Teo referring to love in the romantic sense or the platonic sense? Or both?

[teo123]

@brimstoneSalad, would you also argue that naked mole rats probably feel pain? The general consensus appears to be that they've lost the ability to feel pain because, in their natural environment, their blood is always full of CO2, so their nociceptors fire almost constantly, and would be doing more harm than good if they felt pain. I don't know much about fish metabolism, but I'd guess the pH of their blood is also quite low, since there is not much oxygen in water, and fish move quite a lot.
As for how they survive without being able to feel pain, listen, most of them don't. That's why naked mole rats bring birth to many children, and fish even more so: few of them survive.

[brimstoneSalad]

@brimstoneSalad, would you also argue that naked mole rats probably feel pain?

Yes, they probably do.

The general consensus appears to be that they've lost the ability to feel pain because, in their natural environment, their blood is always full of CO2, so their nociceptors fire almost constantly, and would be doing more harm than good if they felt pain.

They may feel it by other means, having adapted to their over-firing. For example, nerve signals that usually tell them about pressure or another sensation being used to convey physical harm.

As for how they survive without being able to feel pain, listen, most of them don't. That's why naked mole rats bring birth to many children, and fish even more so: few of them survive.

That's due to reproductive strategies of small animals. That's not due to them accidentally hurting themselves on things.

Humans with congenital insensitivity to pain have a serious task of inspecting themselves of injuries regularly. It's a problem.

[teo123]

Yes, they probably do.

Well, I must admit I haven't heard that side of the story. Maybe because nobody specializing in those things would say something like that?

[brimstoneSalad]

Yes, they probably do.

Well, I must admit I haven't heard that side of the story. Maybe because nobody specializing in those things would say something like that?

Like I said, false negatives are more common than false positives. What we're talking about here is speculation, not evidence.

You have to err on the side of assuming any motile organism (moving around the environment) with a brain and nerves feels pain to some measure. The only exception is in organisms where tissue damage is not relevant may not (like a hard bony one, or one that can break apart and heal into more of itself like worms).

[teo123]

Like I said, false negatives are more common than false positives.

Why do you think that's the case? There is clearly a bias to anthropomorphise animal behavior, to not go after the simplest explanation for animal behavior, but to go after an explanation that would make animals look more like humans. Of course, neuroscientists are less prone to that bias than uneducated people are, but it still exists there.

one that can break apart and heal into more of itself like worms

I thought this was actually a myth, that earthworms can't actually do that, and that planarians, which look somewhat like earthworms, but are not actually related to them, can do that, but only in controlled environments.

[brimstoneSalad]

Why do you think that's the case? There is clearly a bias to anthropomorphise animal behavior, to not go after the simplest explanation for animal behavior, but to go after an explanation that would make animals look more like humans.

It's a mistake to assume pain is not the simplest explanation for any animal with a brain. Brains are typically for learning and augmenting behavior and they need feedback to do that.

Of course, neuroscientists are less prone to that bias than uneducated people are, but it still exists there.

There is such a thing as over-correction.

I thought this was actually a myth, that earthworms can't actually do that, and that planarians, which look somewhat like earthworms, but are not actually related to them, can do that, but only in controlled environments.

Many worm species do this, although as I understand it's less reliable for larger ones. It depends where they're broken, how much is lost, etc.
The bottom line is that the larger the cost to tissue damage, the more likely the animal will have mechanisms of pain to help it prevent that damage... unless it doesn't have enough of a brain to use that feedback intelligently enough to be worth it.

[teo123]

It's a mistake to assume pain is not the simplest explanation for any animal with a brain.

OK, now, I think you are falling for the Moravec's Paradox. Pain may seem simple to us (since we have a brain capable of that), but, in reality, it's so complicated that the mechanisms behind it still aren't clear. What is clear is that pain is by orders of magnitude more complicated than, for instance, sight (since sight is explained to such a degree that we can make visual prostheses). It's clearly not something we can say is "the simplest explanation for any animal with a brain".

it doesn't have enough of a brain to use that feedback intelligently enough to be worth it.

Well, considering the well-known fact that fish can't tell which part of their body is being touched... don't you think fish would fail that criteria? That's one of the important arguments used in the Rose's paper "Why Fish Most Likely don't Feel Pain".

[brimstoneSalad]

What is clear is that pain is by orders of magnitude more complicated than, for instance, sight (since sight is explained to such a degree that we can make visual prostheses).

Teo, you just keep saying dumber things.
Visual prostheses are simply stimulating the nerves, they are not beaming visual information into the brain directly without need of interpretation.

The "complicated" matter is interpretation by the brain, which is actually much simpler for pain (easily emulated by Synthetic intelligence) visual processing and image recognition is far more complex.
Now in humans there is also a psychological aspect (phantom pain and nocebo) but that's not required for pain to exist.

You're either being blatantly dishonest here by comparing nerve stimulation to actual reception and processing, or you're so ignorant of this topic that you can't possibly have a fruitful discussion on it.

Read this for starters:

https://en.wikipedia.org/wiki/Pain_in_fish

Pain is the simplest explanation for a whole list of observations.

Any animal with a working brain (as we regard it) is constantly processing positive (pleasure) and negative stimuli, and learning how to optimize the former and avoid the latter. It's the baseline of cognition.
You're into computer science, so you should really research SI/AI if you want to understand how that works.

There might be some animals with more vestigial brains, but considering the cost of nerve tissue that's unlikely.

It's possible for some behaviors to be reflexes, but with the presence of a brain that's unlikely because reflexes are more complicated to evolve and can not be modified so easily (they take generations to reprogram or require more levels of epigenetic coding).

If fish did not feel pain (or something much like it that we would call pain) I might be forced to believe in a god, because nothing but an omniscient creator could pre-program all of the behaviors we see.

Do you think "god did it" is the simplest explanation?

Well, considering the well-known fact that fish can't tell which part of their body is being touched... don't you think fish would fail that criteria?

No, and I don't think that's true anyway (though they may have larger regions with fewer nerves).

That's one of the important arguments used in the Rose's paper "Why Fish Most Likely don't Feel Pain".

Rose is wrong, but he'll never admit it. He's made a number of absurd arguments. He's too invested in his beliefs (and fishing). People like that will just have to die off. Consensus today is that fish probably feel some form of pain.

https://www.smithsonianmag.com/science- ... 180967764/

D. Rose, a professor emeritus of zoology at the University of Wyoming and an avid fisherman who has written for the pro-angling publication Angling Matters. The thrust of their argument is that the studies ostensibly demonstrating pain in fish are poorly designed and, more fundamentally, that fish lack brains complex enough to generate a subjective experience of pain. In particular, they stress that fish do not have the kind of large, dense, undulating cerebral cortices that humans, primates, and certain other mammals possess. The cortex, which envelops the rest of the brain like bark, is thought to be crucial for sensory perceptions and consciousness.

Some of the critiques published by Key and Rose are valid, particularly on the subject of methodological flaws. A few studies in the growing literature on fish pain do not properly distinguish between a reflexive response to injury and a probable experience of pain, and some researchers have overstated the significance of these flawed efforts. At this point, however, such studies are in the minority. Many experiments have confirmed the early work of Braithwaite and Sneddon.

Moreover, the notion that fish do not have the cerebral complexity to feel pain is decidedly antiquated. Scientists agree that most, if not all, vertebrates (as well as some invertebrates) are conscious and that a cerebral cortex as swollen as our own is not a prerequisite for a subjective experience of the world. The planet contains a multitude of brains, dense and spongy, globular and elongated, as small as poppy seeds and as large as watermelons; different animal lineages have independently conjured similar mental abilities from very different neural machines. A mind does not have to be human to suffer.