  We examine the sub-field of philosophy of science using a new method
developed in information science, Referenced Publication Years Spectroscopy
(RPYS). RPYS allows us to identify peak years in citations in a field, which
promises to help scholars identify the key contributions to a field, and
revolutionary discoveries in a field. We discovered that philosophy of science,
a sub-field in the humanities, differs significantly from other fields examined
with this method. Books play a more important role in philosophy of science
than in the sciences. Further, Einstein's famous 1905 papers created a citation
peak in the philosophy of science literature. But rather than being a
contribution to the philosophy of science, their importance lies in the fact
that they are revolutionary contributions to physics with important
implications for philosophy of science.
