A third reason to prevent extinction would be to preserve option value. This could be because of moral uncertainty. Or it could be because understanding these species in the future may provide some other benefits to medicine, wild animal welfare, or some other use yet to be found.
As an illustrative example, if Japanese Dwarf Wheat had gone extinct prior to Borlaug the impact on welfare would have been large and bad.
Option value does not inherently favor biodiversity conservation. Conservation without apparent or rationally expected benefits is a costly gamble that can be won but also lost (if it turns out that conserving had less value than not conserving). Imagine you spend resources on conserving a species that will never turn out to be beneficial, or at least less beneficial than having spent the resources on other, more valuable things.
To the extent that moral uncertainty pushes you to give more credence to common sense ethical views, it does point towards prioritizing biodiversity more than a consequentialist view would otherwise imply, as “let’s preserve species” and “let’s preserve option value” are common sense ethical views. Probably not enough to affect prioritization in practice though.
A third reason to prevent extinction would be to preserve option value. This could be because of moral uncertainty. Or it could be because understanding these species in the future may provide some other benefits to medicine, wild animal welfare, or some other use yet to be found.
As an illustrative example, if Japanese Dwarf Wheat had gone extinct prior to Borlaug the impact on welfare would have been large and bad.
Option value does not inherently favor biodiversity conservation. Conservation without apparent or rationally expected benefits is a costly gamble that can be won but also lost (if it turns out that conserving had less value than not conserving). Imagine you spend resources on conserving a species that will never turn out to be beneficial, or at least less beneficial than having spent the resources on other, more valuable things.
To the extent that moral uncertainty pushes you to give more credence to common sense ethical views, it does point towards prioritizing biodiversity more than a consequentialist view would otherwise imply, as “let’s preserve species” and “let’s preserve option value” are common sense ethical views. Probably not enough to affect prioritization in practice though.