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Measure/Ratio/Proportions/Feynman: since every relationship is largely close to a rational relationship, we can treat every relationship as precisely as we wish.
Proportionality/To the Square/Feynman/(s): proportionality is not simply about "correspondence", otherwise we could say that it did not matter whether something is proportional to the simple or the square. It is rather about the fact that the sizes are the same, if different baselines are chosen.
Vom Wesen physikalischer Gesetze München 1993
Vorlesungen über Physik I München 2001