Patent thickets are empirically false

Another common critique of patents that is based largely on the “rewards” view is that IP rights block incremental inventions.141 This concern is applied to both individual patents and to sets of complementary patents, referred to as patent hold-ups, patent thickets, patent logjams, or the anticommons. Little if any evidence is advanced for these policy concerns.

However, the history of patents demonstrates that the patent system has accommodated a continual stream of both major inventions and incremental inventions. As Adam Mossoff observes, “From the sewing machine to automobiles to airplanes to radios, incremental innovation is omnipresent in the historical evolution of science and technology.”142 George Selgin and John Turner explain how James Watt’s steam engine patent did not prevent subsequent innovations, but “may actually have hastened the development of the high-pressure steam engine by inspiring Richard Trevithick to revive a supposedly obsolete technology so as to invent around them.”143

The many contributions of patents to the development of inventions and the introduction of innovations are well documented. Ron Katznelson and John Howells find that “court decisions upholding Edison’s patent generated a surge of patent filings in the incandescent lamp classes.”144 In the early aircraft industry, Katznelson and Howells find “plentiful evidence of robust US aircraft developments in 1912–1916, the period of the alleged patent hold-up.”145 In the early radio industry, Howells and Katznelson demonstrate that the diode patent was followed by extensive and vigorous development of the later triode technology.146