Something like that will gradually happen between humans and animals. Not the equality part—sorry, PETA—but the ability part. Every week we learn something new about animal brainpower. Crows fashion leaves and metal into tools. Ravens understand spying. Pigeons deceive each other. Rats run mazes in their dreams. Prairie dogs make different sounds to denote different animals. Dolphins teach their young to use sponges as protection. Elephants can mimic trucks. Chimps can pick locks. Parrots can work with numbers. Dogs can learn words from context. Caterpillars can build webs to catch snails. Octopuses can use some arms to disguise themselves while using other arms to sneak away.
As technology makes it easier to do without animals for food and labor—a trend illustrated by cars in the present, and laboratory-grown meat in the future—our increasing awareness of animal intelligence will prod us to give up the worst offenses, starting with butchery of higher mammals. We won't do this because we pity them for being locked up. We'll do it because we respect them for picking locks. And we'll still use chimps to test our drugs, because the faculties worth respecting in them are that much more powerful in us. "We Are All Animals," PETA pleads in the title of its exhibit. Yes, we are. But some animals are more equal than others.