The shrimp welfare project

Apologies for focusing on just one sentence of this article, but I feel like it's crucial to the overall argument:

> ... if [shrimp] suffer only 3% as intensely as we do ...

Does this proposition make sense? It's not obvious to me that we can assign percentage values to suffering, or compare it to human suffering, or treat the values in a linear fashion.

It reminds me of that vaguely absurd thought experiment where you compare one person undergoing a lifetime of intense torture vs billions upon billions of humans getting a fleck of dust in their eyes. I just cannot square choosing the former with my conscience. Maybe I'm too unimaginative to comprehend so many billions of bits of dust.

I don’t really doubt that it’s in principle possible to assign percentage values to suffering intensity, but the 3% value (which the source admits is a “placeholder”) seems completely unhinged for an animal with 0.05% as many neurons as a chicken, and the source’s justification for largely discounting neuron counts seems pretty arbitrary, at least as presented in their FAQ.

The ratio of the neuron numbers may be somewhat meaningful when comparing vertebrates with vertebrates and arthropods with arthropods, but it is almost completely meaningless when comparing vertebrates with arthropods.

The reason is that the structure of the nervous systems of arthropods is quite different from that of the vertebrates. Comparing them is like comparing analog circuits and digital circuits that implement the same function, e.g. a number multiplier. The analog circuit may have a dozen transistors and the digital circuit may have hundreds of transistors, but they do the same thing (with different performance characteristics).

The analogy with comparing analog and digital circuits is quite appropriate, because parts of the nervous systems that have the same function, e.g. controlling a leg muscle, may have hundreds or thousands of neurons in a vertebrate, which function in an all-or-nothing manner, while in an arthropod the equivalent part may have only a few neurons that function in a much more complex manner in order to achieve fine control of the leg movement.

So typically one arthropod neuron is equivalent with much more vertebrate neurons, e.g. hundreds or even thousands.

This does not mean that the nervous system of arthropods is better than that of vertebrates. They are optimized for different criteria. Neither a vertebrate can become as small as the smallest arthropods, nor an arthropod can become as big as the bigger vertebrates, the systems that integrate the organs of a body into a single living organism, i.e. the nervous system and the circulatory and respiratory systems, are optimized for a small size in arthropods and for a big size in vertebrates.

Interesting.

I'm fairly puzzled by sensation/qualia. The idea that there's some chemical reaction in my brain which produces sensation as a side effect is very weird. In principle it seems like you ought to be able to pare things down in order to produce a "minimal chemical reaction" for suffering, and do "suffering chemistry" in a beaker (if you were feeling unethical). That's really trippy.

People often talk about suffering in conjunction with consciousness, but in my mind information processing and suffering are just different phenomena:

* Children aren't as good at information processing, but they are even more capable of suffering.

* I wouldn't liked to be kicked if I was sleeping, or blackout drunk, even if I was incapable of information processing at the time, and had no memory of the event.

So intuitively it seems like more neurons = more "suffering chemistry" = greater moral weight. However, I imagine that perhaps the amount of "suffering chemistry" required to motivate an organism is actually fairly constant regardless of its size. Same way a gigantic cargo ship and a small children's toy could in principle be controlled by the same tiny microchip. That could explain the moral weight result.

Interested to hear any thoughts.

While in animals with complex nervous systems like humans and also many mammals and birds there may be psychological reasons for suffering, like the absence or death of someone beloved, suffering from physical pain is present in most, if not all animals.

The sensation of pain is provided by dedicated sensory neurons, like other sensory neurons are specialized for sensing light, sound, smell, taste, temperature, tactile pressure, gravity, force in the muscles/tendons, electric currents, magnetic fields, radiant heat a.k.a. infrared light and so on (some of these sensors exist only in some non-human animals).

The pain-sensing neurons, a.k.a. nociceptors, can be identified anatomically in some of the better studied animals, including humans, but it is likely that they also exist in most other animals, with the possible exception of some parasitic or sedentary animals, where all the sense organs are strongly reduced.

So all animals with such sensory neurons that cause pain are certain to suffer.

The nociceptors are activated by various stimuli, e.g. either by otherwise normal stimuli that exceed some pain threshold, e.g. too intense light or noise, or by substances generated by damaged cells from their neighborhood.

Interesting. So how about counting nociceptors for moral weight?

What specifically makes it so the pain neurons cause pain and the pleasure neurons cause pleasure? Supposing I invented a sort of hybrid neuron, with some features of a pain neuron and some features of a pleasure neuron -- is there any way a neuroscientist could look at its structure+chemistry and predict whether it will produce pleasures vs pain?