In my mind, the meaning of words such as āsmallā and ālargeā is always context-dependent. In this case, I think it is fair to say that the impact, measured as the number of deaths, from marine plastic pollution on seabirds and marine animals is small in comparison with the impact of catching fish.
In order to make comparisons between species, I think it is worth having in mind the number of neurons (a proxy for sentience) respecting each death toll.
Geometric mean of the neurons for āHarp sealā and āKiller whaleā, which are the species in this list with the least and most neurons that are marine mammals.
Seabirds: 606 M.
Geometric mean of the neurons for āMallardā and āMute swanā, which are the animals in this list with the least and most neurons that look somewhat similar to seabirds.
Fish: 10 M (see āAdult zebrafishā in this list).
I appreciate your quantitative thinking. But I believe itās unfair to say that a fish is 10,000X worth less than a human because a fish has fewer neurons. What if suffering has a minimum threshold of neurons and then declining marginal suffering after that? We donāt know (as you point out in your last paragraph).
āNot everything that can be counted counts and not everything that counts can be counted.ā āEinstein
Great to know that you found it useful!
In my mind, the meaning of words such as āsmallā and ālargeā is always context-dependent. In this case, I think it is fair to say that the impact, measured as the number of deaths, from marine plastic pollution on seabirds and marine animals is small in comparison with the impact of catching fish.
In order to make comparisons between species, I think it is worth having in mind the number of neurons (a proxy for sentience) respecting each death toll.
Estimates for the number of neurons:
Humans: 86 G (see this).
Marine mammals: 7.10 G.
Geometric mean of the neurons for āHarp sealā and āKiller whaleā, which are the species in this list with the least and most neurons that are marine mammals.
Seabirds: 606 M.
Geometric mean of the neurons for āMallardā and āMute swanā, which are the animals in this list with the least and most neurons that look somewhat similar to seabirds.
Fish: 10 M (see āAdult zebrafishā in this list).
Number of neurons respecting each death toll:
Malaria: 627 k * 86 G = 53.9 P.
Marine mammals: 100 k * 7.10 G = 0.710 P.
Seabirds: 1 M * 606 M = 0.606 P.
Fish: 1.62 T * 10 M = 16.2 kP.
Consequently, the number of neurons regarding:
Marine mammals and seabirds is similar.
Malaria is ~ 2 orders of magnitude larger than that of marine mammals /ā seabirds.
Fish is ~ 2.5 orders of magnitude larger than that of malaria.
From the above, it naively seems that:
The death toll of marine mammals /ā seabirds caused by marine plastic pollution is small relative to the death toll caused by malaria.
The death toll caused by malaria is small relative to the death toll concerning wild fish catch.
However, this is not by all means a definite analysis:
It is unclear whether sentience should be measured as a linear function of the number of neurons (see section āBrain sizeā of this page).
Even for the same level of sentience, the intensity of the death could vary.
There are other effects which are not captured by the number of deaths.
I didnāt know fish had 10M neurons. Thanks!
I appreciate your quantitative thinking. But I believe itās unfair to say that a fish is 10,000X worth less than a human because a fish has fewer neurons. What if suffering has a minimum threshold of neurons and then declining marginal suffering after that? We donāt know (as you point out in your last paragraph).
āNot everything that can be counted counts and not everything that counts can be counted.ā
āEinstein
Yes, I agree, there is lots of uncertainty! Moreover:
In addition to the importance of the death toll, one has to take into account its neglectedness and tractability.
Longterm effects should also be assessed, as they can concern most the expected impact of averting deaths (e.g. via expansion of the moral circle).