Human beings lack any evidence for the position that non-human entities have intrinsic value as a mind-independent property. For any possible world alleged to have such intrinsic value, it is possible to conceive another world that is identical in terms of observable properties but that lacks intrinsic value. Accordingly, inferring the intrinsic value of a non-human from some set of observable properties is unjustified, since the same set of observable properties could exist in an otherwise identical world that lacks intrinsic value. Assuming that humans do not have a faculty of intuition that would allow them to perceive unobservable properties like intrinsic value directly, humans have no evidence for the existence of intrinsic value in non-humans. Hence, the position that some non-humans have intrinsic value is unjustified.
Ethics & the Environment
Svoboda, Toby, "Why there is no evidence for the intrinsic value of non-humans" (2011). Philosophy Faculty Publications. 24.
Svoboda, Toby. "Why there is no evidence for the intrinsic value of non-humans." Ethics & the Environment 16.2 (2011): 25-36.