Several influential EAs have suggested using neuron counts as rough proxies for animalsā relative moral weights. We challenge this suggestion.
We take the following ideas to be the strongest reasons in favor of a neuron count proxy:
neuron counts are correlated with intelligence and intelligence is correlated with moral weight,
additional neurons result in āmore consciousnessā or āmore valenced consciousness,ā and
increasing numbers of neurons are required to reach thresholds of minimal information capacity required for morally relevant cognitive abilities.
However:
in regards to intelligence, we can question boththe extent to which more neurons are correlated with intelligence and whether more intelligence in fact predicts greater moral weight;
many ways of arguing that more neurons results in more valenced consciousness seem incompatible with our current understanding of how the brain is likely to work; and
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.
Overall, we suggest that neuron counts should not be used as a sole proxy for moral weight, but cannot be dismissed entirely. Rather, neuron counts should be combined with other metrics in an overall weighted score that includes information about whether different species have welfare-relevant capacities.
Hi David,
Relatedly, readers may want to check Why Neuron Counts Shouldnāt Be Used as Proxies for Moral Weight. Here are the key takeaways: