I walk down the track to talk to my good friends the sky and the fields, and notice that it has just started to rain, but only slightly. How much rain is ‘only slightly’? I do not know. What would I say to a pushy pedant who might ask, “How much rain is ‘only slightly’?” I don’t know. It scares me that I would not know what to say to a pushy pedant about the amount of rain; he might think I’m being stupid or evasive.
I walk past a field, still worried. There are seven cows in the field. Remembering that cows lie down when it is raining, I am impressed to see that while four of the cows are lying down, three remain standing. Relieved that I can rely on such a scientific basis for a calculation about the amount of rain which is currently falling, I no longer feel scared. The next time I meet a pushy pedant who wants to know exactly what I mean by ‘only slightly’ (with regard to rain), I can confidently assert, “What do I mean by ‘only slightly’? I mean that it was precisely 4/7 of a cow’s worth of rain.”