Why no one has a good approach to animal welfare

Surely it seems reasonable to count the welfare of animals -- or at least selected high-cognition animals -- for something rather than nothing.  But this throws moral calculations into a funk.  Even if you count individual animals for very little, there are many billions of them.

Was it a good idea for humans to have settled the New World?  I'll answer yes without hesitation.  But what if billions of other mammals died -- in net terms -- as a result?  I don't want my answer to depend on my relative weighting scheme for animal vs. human welfare.  Nor would I kill a good friend to save the lives of a million cats.  Or a billion cats for that matter.  Yet I still wish to count cats for something positive.  The Humane Society is not a waste of resources.

We might argue that the value of animal lives, as we sum them up, hits some asymptotic limit.  But if that limit binds, we are back to not caring about individual cats -- evaluated at the relevant margin -- much more than epsilon.

It is disquieting that so many fascist thinkers have held animal welfare in high regard.  Once we start counting animals in our moral theory, we too easily get used to the idea that violent conflict is an inevitable part of nature.  Human vs. rat, and of course tiger vs. deer as well.  How can we segregate this apparent endorsement of violence away from human-to-human affairs?  Life as a secular moral thinker is difficult.

The issue of animal welfare provides the strongest available case for moral holism.  It would solve many problems to evaluate states of affairs as wholes, rather than adding up, or otherwise weighting, goods and bads from the constituent parts of those wholes.  But being an individualist at heart, I am reluctant to extend such holism to human affairs.  And even holism must resort to additive consequentialist reasoning to address a variety of practical questions at the margin.

Alternatively, we might develop a moral theory which is neither strictly lexical nor strictly additive in terms of how it treats value.  For that achievement we would have to award a Nobel Prize for moral philosophy...