The Utilitarians Assumed that the Patent System Was Responsible for the Greater Part of Inventing Activity but They All Failed to Ask Themselves about the Opportunity Costs of Inventing

The economists of the early nineteenth century who considered the question were as definite as Professor J. B. Clark that inventions would practically cease if the patent system were abandoned. Jeremy Bentham was in no doubt at all (Rationale of Reward): " With respect to a great number of inventions in the arts, an exclusive privilege is absolutely necessary in order that what is sown may be reaped.... He who has no hope that he shall reap will not take the trouble to sow." John Stuart Mill's argument was similar. (Principles of Political Economy, Book V., ch. x, s. 4.) As Professor Taussig said, the utilitarians assumed that the patent system was responsible for the greater part of inventing activity. The question which they one and all failed to ask themselves, however, is what these people would otherwise be doing if the patent system were not diverting their attention by the offer of monopolistic profits to the task of inventing. By what system of economic calculus were they enabled to conclude so definitely that the gain of any inventions that they might make would not be offset by the loss of other output? By no stretch of the imagination can the inventing class be assumed to be otherwise unemployable. Other product which is foregone when scarce factors are diverted in this way completely escaped their attention.

--Arnold Plant, "The Economic Theory Concerning Patents for Inventions," Economica 1, no. 1 (February 1934): 39-40.