[Montaigne] was not the only writer of his time to oppose hunting or torture. What is unusual in Montaigne is his reason for it: his visceral rapport with others. When speaking to the Brazilian Indians in Rouen, he was struck by how they spoke of men as halves of one another, wondering at the sight of rich Frenchmen gorging themselves while their “other halves” starved on their doorstep. For Montaigne, all humans share an element of their being, and so do all other living things. “It is one and the same nature that rolls its course.” Even if animals were less similar to us than they are, we would still owe them a duty of fellow-feeling, simply because they are alive.
There is a certain respect, and a general duty of humanity, that attaches us not only to animals, who have life and feeling, but even to trees and plants. We owe justice to men, and mercy and kindness to other creatures that may be capable of receiving it. There is some relationship between them and us, and some mutual obligation.
This obligation applies in trivial encounters as well as life-or-death ones. We owe other beings the countless small acts of kindness and empathy that Nietzsche would describe as “goodwill.” After the passage just quoted, Montaigne added this remark about his dog:
I am not afraid to admit that my nature is so tender, so childish, that I cannot well refuse my dog the play he offers me or asks of me outside the proper time.
He indulges his dog because he can imaginatively share the animal’s point of view: he can feel how desperate the dog is to banish boredom and get his human friend’s attention. Pascal mocked Montaigne for this, saying that Montaigne rides his horse as one who does not believe it to be his right to do so, and who wonders whether “the animal, on the contrary, ought really to be making use of him.” This is exactly right – and, as much as it annoyed Pascal, it would have pleased Nietzsche, who final mental breakdown is (unreliably) reported to have begun with his flinging his arms around a horse’s neck on a Turin street and bursting into tears.
Sarah Bakewell, How to Live, pp 179-180