"We usually proceed from a trivial definition: intelligence is the attribute of man that separates his activity from that of the animals. It’s a kind of attempt to distinguish the master from the dog, who seems to understand everything but can’t speak. However, this trivial definition does lead to wittier ones. They are based on depressing observations of the aforementioned human activity. For example: intelligence is the ability of a living creature to perform pointless or unnatural acts."