accumulate. The chemists in the 19th century knew less about chemistry than the chemists in the 20th century, and they in turn knew less than the chemists in the 21st century. Looking forward, today's chemists reasonably expect that chemists in future centuries will know more than they do.

From the 18th century through late 20th century, the history of science, especially of the physical and biological sciences, was often presented as a progressive accumulation