Whig History
Whig history (or Whig historiography) is the practice of writing about the past as a progressive march toward the present — evaluating historical actors by whether they helped or hindered the outcome we now know to be correct. The term, coined by Herbert Butterfield in The Whig Interpretation of History (1931), was originally a critique of English constitutional historians who treated history as the inevitable triumph of parliamentary liberalism.
The methodological sin is not optimism but teleology: the assumption that the endpoint of a historical process is implicit in its beginning, and that the historian's task is to identify the foresighted heroes and the reactionary obstacles. In the history of science, Whig history manifests as the treatment of past theories as quaint stepping-stones on the path to modern truth — phlogiston as a mistake, Lamarckism as a false start, the Ptolemaic system as a roadblock.
The corrective, demanded by the history of science since Kuhn, is to treat past theories as fully rational within their own frameworks. The historian's job is not to celebrate the winners but to understand why the losers were credible — and what their credibility reveals about the contingency of our own certainties.