From the letters to a young technologist:
history teaches you that nothing about our present-day reality was inevitable. The “natural order of things”—going to school, using electricity, believing in human rights, having a job, the existence of hallways, communicating in writing—is a human invention, and human inventions are the product of highly contingent cultural forces and individual decisions.
Understanding the past, helps build the intuition that we stand on the shoulders of giants. Nothing was just the way it was, even things we take for granted everyday.
Don’t attempt to change something until you understand why it exists in the first place. Obtaining that understanding of course requires a detailed study of history.
History enables us to recognize the present as contingent, and therefore view the future as unwritten. It situates us in a lineage and grounds us in a tradition upon which we may build.
Also from Pieces of the Action by Vannevar Bush:
The study of history can aid in avoiding mistakes, provided it is recent history and accurate, that is, before it has degenerated into myth.