I have criticized the law of Labour Value with all the
severity that a doctrine so utterly false seemed to me to deserve. It may be that my criticism also is open to
many objections. But one thing at any rate seems to me certain: earnest writers concerned to find out the truth
will not in future venture to content themselves with asserting the law of value as has been hitherto done.
In future any one who thinks that he can maintain this law will first of all
be obliged to supply what his predecessors have omitted--a proof that can be taken seriously. Not quotations from authorities;
not protesting and dogmatising phrases; but a proof that earnestly and conscientiously goes into the essence of the matter.
On such a basis no one will be more ready and willing to continue the discussion than myself.
--Eugen von Bohm-Bawerk. Capital and Interest p. 389