We examine the welfare costs of animal death within a consequentialist total utilitarian framework that treats sentience as the intrinsic value of living beings. In moral philosophy and neuroscience, sentience is defined as the capacity for valenced experience. Under plausible neuroscientific assumptions, performance on cognitive tests provides a conservative lower bound on sentience. The authors estimate the relationship between cognition and neuron counts in order to cardinalize sentience.

To do so, they compile population and neuron data for a broad range of animal species and combine them into a single welfare measure. Across a wide range of parameters, they find that the aggregate sentience losses experienced by animals over the past half century exceed the sentience gains to humans from population growth by at least 10,000-fold. In welfare terms, breaking even would require assigning animals a correspondingly small welfare weight. Adding the benefits of economic growth for humans does little to change the overall result, which is why the paper is aimed less at a narrow growth-accounting exercise than at the harder problem of how much moral weight to assign different forms of life.

The paper’s abstract is not, in the view of the post, especially well framed for the underlying question. The post argues that macro welfare comparisons are most meaningful where gains from trade are possible, which applies across humans and also, in some cases, across humans and dogs. It says that non-human animal welfare should be improved at the margin, but that larger comparisons across totals are not something the author can make. The post adds that humans are inevitably on the side of humans and are not obligated, as welfarists, to commit collective suicide in order to replenish the earth’s biodiversity.

The title of the paper is somewhat misleading: “The Intrinsic Valuation of Biodiversity Loss.” The authors are Adrien Bilal, Noémie Pinardon-Touati, and Conor Walsh.