All history is relevant, but the history of technology is the most relevant.
Kranzberg's fifth law is a claim about curriculum rather than causation, and the weakest of the six. The first is the one that carries.
In practice
- A syllabus that covers the causes of a war and not the railways that moved the armies has made a choice about what counts as history.
- A history of the twentieth century that omits the shipping container, the contraceptive pill and the transistor is missing more than one that omits a treaty, which is the defensible version.