Chapter 9 of Reason and Ethics presents a detailed case study of one application of desirism – in both theory and practice – to a highly contested issue in animal (or medical) ethics, namely, whether laboratory experimentation on nonhuman animals is justified. Unlike eating animals (in the United States anyway), using them for medical and even basic research can plausibly be argued to be a matter of life and death for human beings. That is the basis for the standard utilitarian defense. Meanwhile, a desirist who happens not to want any animals, human or otherwise, to be subjected to breeding, confinement, procedures, and finally “sacrifice” or “euthanasia” of this sort, has, qua amoralist, no moral argument to offer on behalf of her preference. This chapter makes two main points about this asymmetry. One is that the desirist can still mount an effective rebuttal against the defender’s argument, in this case by exploding the claim that animal experimentation is humane, without in any way compromising her amoralist commitments. The other is that the rebuttal is more likely to be effective not only logically but also psychologically for having been grounded amorally rather than morally.