Nº 20-90: Are 'Flow of Ideas' and 'Research Productivity' in Secular Decline?

It is widely held true that fundamental scientific knowledge has been accelerating exponentially over the past centuries and will continue to do so for the foreseeable future. Moreover, endogenous growth theory postulates that this exponential accumulation of knowledge is the main source of the ubiquitous exponential economic growth. We test these claims by constructing two new series of knowledge indices, one representing the historical evolution of the Flow of Ideas, the other of the Research Productivity, for the time period between 1750 and 1988. Three different geographical regions are covered: 1) Continental Europe, 2) the United Kingdom, and 3) the United States; and two disciplines: a) the physical sciences, and b) the life sciences. Our main result is that scientific knowledge has been in clear secular decline since the early 1970s for the Flow of Ideas and since the early 1950s for the Research Productivity. We also observe waves coinciding with the three industrial and technological revolutions, in particular in the United Kingdom. Overall, our results support the Kuhnian theory of knowledge creation through scientific revolutions, punctuation and paradigm shifts and falsify the gradualism that lies at the basis of the currently prevailing economic paradigm of endogenous growth.