Moral philosophers, even those belonging to the Critical School [the followers of Kant and Fries], have often represented duties to animals as indirect duties to oneself or to other men. For instance, maltreatment of animals is forbidden on the ground that it encourages cruelty, that is, a disposition that obstructs fulfillment of duty. Now, maltreatment of animals may have just that effect; nevertheless the argument in question takes no account of the whole truth. For according to this argument, maltreatment of animals is reprehensible because of the incidental effects it has on the character of the agent or of other men. Where the effects are not harmful, maltreatment of animals would thus be permitted.
If we examine the arguments on the basis of which the existence of direct duties to animals has been denied, we are compelled to conclude regretfully that most of these arguments are sophistical—indeed, they are so threadbare that we find it surprising that they could be advanced by people who claim to be schooled in scientific method. The treatment this problem has received in ethics would be devastating testimony to the limitations of human understanding, if it were not clear that interest rather than error accounts for it.
(
Leonard Nelson,
System of Ethics, trans. Norbert Guterman [New Haven: Yale University Press, 1956], 137 [footnote inserted into text in brackets])
