But if fire could be kindled only by a particular sort of match which Prometheus alone could make, the fact that he was really the lighter of all fires would be obvious, and his claim to a payment in respect of the lighting of every one of them would be as sound as the claim of the lighter of street-lamps to his wages.

If "Man and Superman" were not a play, but a hoot, which Mr.
Shaw had invented in order to call attention to himself, and which any street boy could imitate with the same results, it would be idle for Mr.
Shaw to claim a right to royalties from the street boys; but it would be idle only because it would not be possible to collect them.

He is able to collect them on his play because, and only because, his play exists in a form which is susceptible of legal protection.

If in justice he has a right to these, as he no doubt has, he would, if abstract justice were the sole determining factor, have an equal right to royalties on the use of his peculiar hoot.

He fails to have any such right because, as a matter of fact, the principle of abstract justice with which we are here concerned--that every one has a right to everything that he himself produces--has, in common with all abstract moral principles whatsoever, no application to cases in which, from the nature of things, it is wholly impossible to enforce it.
And the same criticism is applicable to the other argument before us, which admits that a man who invents a productive machine, or who writes a remunerative play, is, so long as he lives, entitled, because he is the true producer of them, to certain profits arising from the use of either; but adds that his rights to such profits end with his own life, and lose all sanction in justice the moment they are transferred to an heir.