Excerpts - Zoo

Aquariums weren't ok because, honestly, he should like to watch the torment of panting big cats and polar bears prowling back and forth all day, than have to regard a species unaware of - or at least unable to convey - the knowledge that it was trapped. For, said Austerlitz, a great fear nagged at him, for whatever it might imply, that beside Plank's or Newton's constants it might be as easy to determine - via summation of a species' mean intelligence - the safe distance at which a hand is able to place its pet from the borders of what it otherwise recognises as freedom.