What would it be like for her to be on this walk? Would she, like him, feel part of a web of living experience? Francis couldn’t help wondering how Olivia’s relationship to the natural world had withstood her training as a biologist. So much biology consisted of killing animals, during or after performing experiments on them, it was an education that cried out for dissociation from the rest of nature. It had never been a good time to be a ‘model organism’, a fruit fly, a mouse, a dog, a rat, a cat, a rhesus monkey or a chimpanzee. As an undergraduate, he had done more than enough vivisection, dissection and deliberate infection of laboratory animals to drive him to specialise in botany as soon as possible. Why did every generation of biology student have to amputate the legs of living frogs and spectate on the beating hearts of crucified mammals, as if they were trying to join a tough gang whose rite of passage was a random murder? At the peak of his rebellion against this tradition, he had come across a remark by Wittgenstein, not especially eloquent in itself, but striking at the time, because it seemed to vindicate his unease about the way he was being taught: ‘Physiological life is of course not “Life”. Nor is psychological life. Life is the world.’ He might not have made the grade as a lethal biologist, but he remained a naturalist, trying to appreciate the last of those three short sentences as deeply as he could. Being a naturalist wasn’t a bad tradition; after all, before neo-Darwinism there had been Darwinism and before Darwinism, Darwin, a man writing about earthworms and making detailed observations of living creatures and joining pigeon fancying clubs and gardening and corresponding with other naturalists, without treating their testimony as ‘merely anecdotal’.