The 18th Century philosopher Immanuel Kant is one of history's true titans, perhaps the most influential thinker of the last millennium. His philosophy on animals, however, was still rooted in a time and place that understood and expected little of the nonhuman mind. Yes, Kant said, animals feel pain, marked improvement on Descartes' unfeeling "automata," but they "are not self-conscious and are there merely as a means to an end. That end is man." Animals are "man's instruments."
In refraining from animal cruelty (not vivisection and butchery, which Kant thought justified), we cultivate good behavior towards our fellow human beings: "If he is not to stifle his human feelings, he must practise kindness towards animals, for he who is cruel to animals becomes hard also in his dealings with men. We can judge the heart of a man by his treatment of animals." In short, "Our duties towards animals are merely indirect duties towards humanity."
Kant's philosophy foreshadowed our contemporary analysis of serial killers: "Hogarth depicts this in his engravings. He shows how cruelty grows and develops. He shows the child's cruelty to animals, pinching the tail of a dog or a cat; he then depicts the grown man in his cart running over a child; and lastly, the culmination of cruelty in murder." Beware the child-torturer of neighborhood cats, for one day he may graduate to people.
But what if data revealed otherwise? What if, instead of moving on, the wicked among us found a final, satisfying outlet in abusing animals? In a Kantian world, the end - protecting morally relevant human beings from potential future harm - would justify the means - the torture and destruction of morally irrelevant animals. After all, says Kant, even though vivisectionists "certainly act cruelly...their aim is praiseworthy." The cruelty, in other words, is justified.
Still, unlike Descartes, there are hints of ambivalence in Kant's words: "Animal nature has analogies to human nature... The more we come in contact with animals and observe their behaviour, the more we love them, for we see how great is their care for their young. It is then difficult for us to be cruel in thought even to a wolf." We should not shoot a dog who is no longer useful; instead, he "deserves reward" and should be kept "until he dies."
If Kant were here today, it is not difficult to imagine him espousing animal rights. Ethological studies demonstrating animal intelligence, even self-consciousness, would have astounded him. Also, the uses he considered necessary (food, research) are now no longer so. Moreover, with Christianity's reach (intimidation) but a whisper of what it was in 1795, Kant's genius would be fully freed, allowed to follow the lines of rational thought without fear of the inquisitor or eternal damnation. Indeed, I see a 21st Century Kant as a Singer, Regan, or Francione, for he was too gifted for it to be otherwise.