A chat suggestion that cryptanalysis should have received more interwar effort prompts a warning about evidentiary limits. An outside observer cannot know how much work was being done in secret, and parts of the Bletchley Park record remained sealed even decades later. Intelligence history is therefore unusually vulnerable to arguments from silence because the surviving public archive may omit successful preparation as well as failure. The watch point offers a useful caution for judging secret capabilities only through declassified evidence.
Notable Point · 50:44-51:20
Why visible records can understate interwar cryptanalysis
Claims that Britain neglected cryptanalysis must account for intelligence work that remained secret or whose records are still closed.