 Kuhn’s book was his attempt to answer the question posed by the above quotation. This question immediately raised another: How can appeal to history achieve that transformative change? In particular, how can descriptive claims about the past (or present science, for that matter) affect our normative judgments about rational beliefs and behaviors? How can history inform a methodology of science? This is a version of the so-called “is-ought” problem. Can there really be a “judgment” of history?