Practical jokes are a demonstration that the distinction between seriousness and play is not a law of nature but a social convention which can be broken, and that a man does not always require a serious motive for deceiving another.
Two men, dressed as city employees, block off a busy street and start digging it up. The traffic cop, motorists and pedestrians assume that this familiar scene has a practical explanation – a water main or an electric cable is being repaired – and make no attempt to use the street. In fact, however, the two diggers are private citizens in disguise who have no business there.
All practical jokes are anti-social acts, but this does not necessarily mean that all practical jokes are immoral. A moral practical joke exposes some flaw of society which is hindrance to a real community or brotherhood. That it should be possible for two private individuals to dig up a street without being stopped is a just criticism of the impersonal life of a large city where most people are strangers to each other, not brothers; in a village where all inhabitants know each other personally, the deception would be impossible.