has given a cheque to another man
steals back half the money as soon as the cheque is cashed.

Now, both these arguments, so far as they go, are true; but neither has
any bearing on the problem which is now before us. That problem
arises--let me observe once more--out of the assumption that, as a
matter of justice, every man has a right to the products of all such
forces as are his own; whence it follows that nobody has a right to the
products of any forces which are not definitely in himself. Let us
take, then, the latter of the above arguments first. It would doubtless
be absurd to contend, were Prometheus alive to-day, that because he
invented the art of striking fire from flints he ought to be paid a
tribute by every savage who boiled a kettle; for the savage can strike a
flint as well as Prometheus himself could. 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;