I don't expect I'll reply further

You are welcome to return to this later. I would be curious to know your thoughts.

EV is subjective. I'd recommend this post for more on this.

I liked the post. I agree EV is subjective to some extent. The same goes for the concept of mass, which depends on our imperfect understanding of physics. However, the expected mass of objects is still comparable, unless there is only an infinitesimal difference between their mass.

Thanks for sharing!

This report is written in a governing thoughts structure; the contents serve as a high level summary:

Nitpick. I think the section would have been more readable if you had writted it in the following format.

• Bullet 1 (link)

  • Sub-bullet 1 (link)

  • ...

• ...

Then only one word ("link") per line would have a link.

Thanks for sharing, and welcome to the EA Forum, Pawel! You may benefit from checking out the organisations working on interventions related to mental health:

• Recommended by the Happier Lives Institute (HLI):
  • Strong Minds.
  • Friendship Bench.
• Incubated by Ambitious Impact (AIM):
  • Actra.
  • Canopie.
  • Happier Lives Institute.
  • Kaya Guides.
  • Vida Plena.

I don't know exactly what you mean by "feels very hard to compare".

It looks like you are inferring incomparability between the value of 2 futures (non-discrete overlap between their UEVs) from the subjective feeling (in your mind) that their EVs feel very hard to compare (given all the evidence you considered), as any comparisons involve decisive arbitrary assumptions. I mean "arbitrary" as used in common language.

I'd appreciate more direct responses to the arguments in this post, namely, about how the comparison seems arbitrary.

Comparisons among the expected cost-effectiveness of the vast majority of interventions seem arbitrary to me too due to effects on soil animals and microorganisms. However, the same goes for comparisons among the expected mass of seemingly identical objects with a similar mass if I can only assess their mass using my hands, but this does not mean their mass is incomparable. To assess this, we have to empirically determine which fraction of the uncertainty in their mass is irreducible. 10 k years ago, it would not have been possible to determine which of 2 rocks with around 1 kg was the heaviest if their mass only differed by 10^-6 kg. Yet, this is possible today. Some semi-micro balances have a resolution of 0.01 mg, 10^-8 kg. So I would say the expected mass of the rocks was comparable 10 k years ago. Do you agree? There could be some irreducible uncertainty in the mass of the rocks, but much less than suggested by the evidence available 10 k years ago.

Thanks for the comment, David!

My impression is therefore that the strong correlations more reflect the fact that we have a small number of datapoints with animals differing dramatically on a wide variety of predictor (or, in principle, outcome) variables which are all highly correlated, rather than indicating that neuron counts are distinctively predictive of any outcomes of interest. See Andrew Gelman's similar discussion of our study.

I agree. Moreover, in allometry, "the study of the relationship of body size to shape,^[1] anatomy, physiology and behaviour", "The relationship between the two measured quantities is often expressed as a power law equation (allometric equation)". So the logarithm of the individual number of neurons explaining well the logarithm of the welfare ranges means this will also be well explained by many other properties. If the welfare range is roughly proportional to "individual number of neurons"^"exponent 1", and the individual number of neurons is roughly proportional to "property (e.g. individual brain mass)"^"exponent 2", the welfare range will be roughly proportional to "property"^("exponent 1"*"exponent 2"). This means the logarithm of the welfare range will be well explained by the logarithm of "property". Relatedly, here is an illustration of why I think individual welfare per fully-healthy-animal-year could be proportional to "metabolic energy consumption per unit time at rest"^"exponent".

Given the above, I do not think it matters much whether one estimates welfare per unit time based on the individual number of neurons, or another property which is a power law of it. I believe it matters much more than results are presented for many exponents of the power law determining the welfare per unit time. I did this in the post where I estimated the total welfare of animal populations assuming individual welfare per fully-healthy-animal-year is proportional to "individual number of neurons"^"exponent", where I analysed exponents ranging from 0 to 2.

Hi Adam.

• there is no straightforward empirical evidence or compelling conceptual arguments indicating that relative differences in neuron counts within or between species reliably predicts welfare relevant functional capacities.

As illustrated in the graph below, the estimates for the (expected) welfare ranges in Bob Fischer's book about comparing welfare across species, which contains what Rethink Priorities (RP) stands behind now, are pretty well explained by "individual number of neurons"^0.188. I have a post where I estimate the total welfare of animal populations assuming individual welfare per fully-healthy-animal-year is proportional to "individual number of neurons"^"exponent".

Thanks for the post, Walter and Heather!

However, unless we assign only an extremely (and arguably, implausibly) low weighting to animals, their sheer numbers mean that they are still likely to dominate humans by several orders of magnitude.³

[...]

³Current attempts to weight based on neuron count (e.g. MacAskill 2022) are unconvincing (see Shriver 2022 [report by Adam Shriver which was part of Rethink Priorities (RP’s) moral weight project]). [As a side note, you could add the footnotes to the EA Forum post such that people do not have to check the end of the substack post.]

I think the total welfare of humans may be larger than the absolute value of the total welfare of animals more easily than you suggest above. Adam's report concludes “there is no straightforward empirical evidence or compelling conceptual arguments indicating that relative differences in neuron counts within or between species reliably predicts welfare relevant functional capacities”. However, as illustrated in the graph below, the estimates for the (expected) welfare ranges in Bob Fischer's book about comparing welfare across species, which contains what RP stands behind now, are pretty well explained by "individual number of neurons as a fraction of that of humans"^0.188.

Assuming individual welfare per fully-healthy-animal-year is proportional to "individual number of neurons"^"exponent of the number of neurons", I estimate the total welfare of humans is larger than the absolute value of the total welfare of:

• Cattle, hens, broilers, and farmed black soldier fly (BSF) larvae and mealworms, finfishes, and shrimps for an exponent of at least 0.61.
• Soil ants, termites, springtails, mites, and nematodes for an exponent of at least 1.17.

Below is the graph illustrating this. I believe the exponent may easily be higher than 1, and therefore would not be surprised if the total welfare of humans was much larger than the absolute value of the total welfare of animals.

Hi Wayne. You are right I did not account for the possibility of serious illness.

I have neglected the cost from serious illness, which I expect to be minor for me. However, I believe accounting for it may well make vaccination worth it for people who are, for example, 65 or older.

Here is an estimation of the harm from serious illness which is in agreement with my statement above. The disease burden, which accounts for mortality and morbidity, from lower and upper respiratory infections among people with age 25 to 29 (which covers my age) in Portugal (where I live) in 2023 was 0.00113 DALY/person-year (= (4.98 + 6.29)*10^-4). This corresponds to a loss of 0.413 d/person-year (= 0.00113*365.25), and therefore 3.85 h/year (= 0.413*9.33) less logged in my time sheet assuming all the disease burden from lower and uper respiratory infections is linked to the flu (which overestimates the damage caused by this). I got 2.09 h/year less neglecting serious illness, which suggests this accounts for a loss of 1.76 h/year (= 3.85 - 2.09). However, for the 2024-25 flu season in the US, only "11% of all patients hospitalized with influenza did not have any underlying medical conditions", which applies to me. So I guess my expected harm due to serious illness caused by flus is 11 % as large, and implies logging 0.194 h/year (= 1.76*0.11) less in my time sheet. As a result, I estimate the harm from serious illness is 9.28 % (= 0.194/2.09) of my original estimate neglecting serious illness.

Thanks for clarifying, Hannah! How much dedicated funding would you have to receive to scope out projects (without commiting to doing a project)? 

Hi Carl.

the life expectancy of civilization is very long

Decreasing the risk of human extinction over the next few decades is not enough for astronomical benefits even if the risk is concentrated there, and the future is astronomically valuable. Imagine human population is 10^10 without human extinction, and that the probability of human extinction over the next 10 years is 10 % (in reality, I guess the probability of human extinction over the next 10 years is more like 10^-7), and then practically 0 forever, which implies infite human-years in the future. As an extreme example, an intervention decreasing to 0 the risk of human extinction over the next 10 years could still have negligible value. If it only postpones extinction by 1 s, it would only increase future human-years by 317  (= 10^10*1/(365.25*24*60^2)). I have not seen any empirical quantitative estimates of increases in the probability of astronomically valuable futures.

A classic paper by the climate economist Martin Weitzman shows that the average discount rate over long periods  is set by the lowest plausible rate

The link is broken. Here is the paper "Why the Far-Distant Future Should Be Discounted at Its Lowest Possible Rate".