My personal reasons favouring global health:

1. I'm sceptical of Rethink's moral weight numbers^[1], and am more convinced of something closer to anchoring on neuron counts (and even more convinced by extreme uncertainty). This puts animal charities more like 10x ahead rather than 1000 or 1 million times. I'm also sceptical of very small animals (insects) having a meaningful probability/degree of sentience.
2. I am sceptical of suffering focused utilitarianism^[2], and am worried that animal welfare interventions tend to lean strongly in favour of things that reduce the number of animals, on the assumption that their lives are net negative. Examples of this sort of mindset include this, this, and this.
   
   Not all of these actively claim the given animals' lives must be net negative, but I'm concerned about this being seen as obviously true and baked into the sorts of interventions that are pursued. I'm especially concerned about the idea that the question of whether animals' lives are net-negative is not relevant (see first linked comment), because the way in which it is relevant is that it favours preventing animals from coming into existence (this is more commonly supported than actively euthanising animals).
   
   Farmed animals are currently the majority of mammal + bird biomass, and so ending the (factory) farming of animals is concomitant with reducing the total mammal + bird population^[3] by >50%, and this is not something that I see talked about as potentially negative.
   
   That said, if pushed I would still fairly strongly predict that farmed chickens lives are net negative at least, which is why on net I support the pro animal welfare position.
3. I think something like worldview diversification is essentially a reasonable idea, for reasons of risk aversion and optimising under expected future information. The second is an explore/exploit tradeoff take (which often ends up looking suspiciously similar to risk aversion 🧐).
   
   In the case where there is a lot of uncertainty on the relative value of different cause areas (not just in rough scale, but that things we think are positive EV could be neutral or very negative), it makes sense to hedge and put a few eggs into each basket so that you can pivot when new important information arises. It would be bad to, for instance, spend all your money euthanising all the fish on the planet and then later discover this was bad and that also there is a new much more effective anti-TB intervention.
   
   Of course, this more favours doing more research on everything than it does pouring a lot of exploit-oriented money into Global Health, but in practice I think some degree of trying to follow through on interventions is necessary to properly explore (plus you can throw in some other considerations like time preference/discount rates), and OpenPhil isn't spending money overall at a rate that implies reckless naive EV maximising (over-exploitation).
   
   Some written-down ideas in this direction: We can do better than argmax, Tyranny of the Epistemic Majority, In defense of more research and reflection.
4. I believe something like "partiality shouldn't be a (completely) dirty word". When taken to extremes, most people accept some concessions to partiality. For instance it's generally considered not a good strategic move to pressure people into giving so much of their income that they can't live comfortably, even though for a sufficiently motivated moral actor this would likely still be net positive. Most people also would not jump at the chance to be replaced by a species that has 10% higher welfare.
   
   I think it's wrong to apply this logic only at the extremes, and there should be some consideration of what the market will bear when considering more middle of the road sacrifices. For instance a big factor in the cost effectiveness of lead elimination is that it can be happily picked up by more mainstream funders.

(I realise a lot of these are not super well justified, I'm just trying to get the main points across).

1. ^{^}

   I'm planning to publish a post this week addressing one small part of this, although it's a pretty complicated topic so I don't expect this to get that far in justifying the position

2. ^{^}

   Not meant in a very technical sense, just as the idea that there is probably more suffering relative to positive wellbeing, or that it's easier to prevent it. Again, this is for reasons that are beyond the scope of this post. But two factors are:
   1) I think common sense reasoning about the neutral point of experience is overly pessimistic
   2) I am sceptical of the intensity of pain and pleasure being logarithmically distributed (severe pain ~100x worse than moderate pain), and especially of this being biased in the negative direction. One reason for this is that I find the "first story" for interpreting Weber's law in this post much more intuitive, i.e. that logarithmically distributed stimuli get compressed to a more linear range of experience

3. ^{^}

   Weighted by biomass obviously. The question of actual moral value falls back to the moral weights issue above. A point of reference on the high-moral-weights-sceptical end of the spectrum is this table @Vasco Grilo🔸 compiled of aggregate neuron counts (although, as mentioned, I don't actually think neuron counts are likely to hold up in the long run)

(Edited)

I favour animal welfare, but some (near-term future) considerations that I'm most sympathetic to that could favour global health are:

1. I'm not a hedonist. I care about every way any being can care consciously and terminally about anything. So, I care about others' (conscious or dispositionally conscious) hedonic states, desires, preferences, moral intuitions and other attitudes on their behalf. I'd guess that humans are much more willing to endure suffering, including fairly intense suffering, for their children and other goals than other animals are for anything. So human preferences might often be much stronger than other animals', if we normalize preferences by preferences about one's own suffering, say.
   1. This has some directly intuitive appeal, but my best guess is that this involves some wrong or unjustifiable assumptions, and I doubt that such preferences are even interpersonally comparable.^[1]
   2. This reasoning could lead to large discrepancies between humans, because some humans are much more willing to suffer for things than others. The most fanatical humans might dominate. That could be pretty morally repugnant.
2. Arguments for weighing ~proportionally with neuron counts:
   1. The only measures of subjective welfare that seem to me like they could ground interpersonal comparisons are based on attention (and alertness), e.g. how hard attention is pulled towards something important (motivational salience) or "how much" attention is used. I could imagine the "size" of attention, e.g. the number of distinguishable items in it, to scale with neuron counts, maybe even proportionally, which could favour global health on the margin.
      1. But probably with decreasing marginal returns to additional neurons, and I give substantial weight to the number of neurons not really mattering at all, once you have the right kind of attention.
   2. Some very weird and speculative possibilities of large numbers of conscious or value-generating subsystems in each brain could support weighing ~proportionally with neuron counts in expectation, even if you assign the possibilities fairly low but non-negligible probabilities (Fischer, Shriver & St. Jules, 2022).
      1. Maybe even faster scaling than proportional in expectation, but I think that leads to double counting I'd reject if it's even modestly faster than proportional.
3. Animal welfare work has more steeply decreasing marginal cost-effectiveness.
4. Cost-effectiveness estimates for marginal animal welfare work are more speculative than GiveWell's (RCT- and meta-analysis-based) estimates, at least for the more direct impacts considered. Maybe we're not skeptical enough of the causal effects of animal welfare work, and the welfare reforms would have happened soon anyway or aren't as likely to actually materialize as we think. I'm also inclined to give less weight to more extreme impacts when they're more ambiguous/speculative, similar to difference-making ambiguity aversion.
5. I worry about lots of animal welfare work backfiring, and support for apparently safer work funging with work that backfires, so also backfiring.
   1. My best guess is that animal agriculture is good for wild animals, especially invertebrates, because it reduces their populations and I have very asymmetric views. So plant-based substitutes, cultured meat and other diet change work could backfire, if and because it harms wild invertebrates more than it helps animals used for food.
   2. I worry that nest deprivation for caged laying hens could be much less intensely painful than the long-term pain from keel bone fractures, so cage-free could be worse because of the apparent increase in keel bone fractures.
      1. I think we should support more work to reduce keel bone fractures in laying hens, and CE/AIM wants to start a new charity for this.
6. Saving human lives, e.g. through AMF, probably reduces wild animal populations, so seems good for animals overall if you care enough about invertebrates (relative to animals used for food) and think they'd be better off not existing.
   1. Maybe farmed insect welfare work is even better, though.

1. ^{^}

   People probably just have different beliefs/preferences about how much their own suffering matters, and those preferences are plausibly not interpersonally comparable at all.

   Some people may find it easier to reflectively dismiss or discount their own suffering than others for various reasons, like particular beliefs or greater self-control. If interpersonal comparisons are warranted, it could just mean these people care less about their own suffering in absolute terms on average, not that they care more about other things than average. Other animals probably can't easily dismiss or discount their own suffering much, and their actions follow pretty directly from their suffering and other felt desires, so they might even care more about their own suffering in absolute terms on average.

   We can also imagine moral patients with conscious preferences who can't suffer at all, so we'd have to find something else to normalize by to make interpersonal comparisons with them.

   I discuss interpersonal comparisons more here.

I'm making my way through, but so far I guess it's gonna be @Richard Y Chappell🔸's arguments around ripple effects. 

Animals likely won't improve the future for consciousness, but more, healthy humans might. 

I haven't read the article fully yet though.