Quantifying the “cognitive extent” of science and how it has changed over time and across countries

This essay presents and discusses recent trends in the growth of science in terms of the extent of knowledge in scientific literature rather than from the standpoint of publication volumes. It applies an existing method for evaluating the cognitive content of scientific publications to the entire Web of Science database for the period 1900-2020. It compares the growth dynamics of science based on productivity measures with those based on a concept of “cognitive territory”, finding stagnation in the latter since the mid-2000s. Growth dynamics are also examined for individual fields of research, showing that physics, astronomy and biology are expanding, whereas medicine is stagnating or even contracting. Cognitive extent is compared for different countries. While the People’s Republic of China (hereafter “China”) was the biggest producer of scientific publications in 2019, its papers covered a smaller cognitive extent than many individual West European countries and Japan.