For real sentient beings, though, the truth is more complex. They are not us, but to look into their eyes is to know that someone is in there. Imposing our own specific thoughts and feelings on that someone is in one sense too imaginative, in presuming he could receive the world in the way we do, and in another not imaginative enough, in not opening our minds to the full possibilities of his difference. The philosopher and theologian Martin Buber called this “the immense otherness of the Other,” reflecting on his relationship with a family horse as a child. As he stroked the mane, “it was as though the element of vitality itself bordered on my skin” — “something that was not I,” he notes, but was “elementally” in relation to him. There was an existential connection between them in their improbable blessing of breathing, beating life. And not only life, but the particularity of sentient individuals, as the horse “very gently raised his massive head, ears flicking, then snorted quietly, as a conspirator gives a signal meant to be recognizable only by his fellow conspirator: and I was approved.”