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. In the heir's hands, it is urged, they entirely change their
character, and, instead of enabling a man to secure what is honestly his
own, become means by which he is enabled to steal what morally belongs
to others.

Now, if it is seriously contended that nobody has a right to anything
which at some time or other he has not personally produced, the interest
on machinery, as soon as the inventor dies, not only ought not to belong
to the inventor's heir, but it ought not to belong to anybody; for if
this interest is not produced by the heir, it is certainly not produced
by any of the heir's contemporaries. A contention like this is absurd;
there must therefore be something amiss with the premises which lead up
to it. Socialists who admit that an inventor during his lifetime has a
right to the interest resulting from the use of his own inventions,
endeavour to solve the difficulty by maintaining that after his death
both invention and interest should pass into the hands of the state; but
this doctrine, on whatever grounds it may be defended, cannot be
defended as based on the principle now in question, that the sole valid
title to possession is personal production. It must, if it is based on
any abstract moral principle at all, be based on one of a much more
general kind, according to which the ultimate standard of justice is not
the deeds of the individual, but the general welfare of society.

Here it is true that the appeal is still to abstract justice, but it is
not an appeal to abstract justice only. In order to condemn interest on
any such ground as this, it is necessary to assume or prove that to make
interest illegal, or to confiscate it by taxation when it arises, or by
any other means to render its enjoyment impossible, will as a matter of
fact have the result desired--namely, a permanent rise in the general
level of prosperity. It is only by means of an assumption of this purely
practical kind that the abstract moral principle can be applied to the
case at all; and thus let us approach the problem from whatever side we
will, we are brought from the region of theory down into that of
practice, not, indeed, by an abrupt leap, but by a gradual and necessary
transition. We are not abandoning our considerations of what, in
abstract justice, ought to be; but we are compelled to in