I'm reading The Moon is a Harsh Mistress right now (fascinating, bizarre, and highly enjoyable thus far), and there's a moment where the main characters discuss

I'm reading The Moon is a Harsh Mistress right now (fascinating, bizarre, and highly enjoyable thus far), and there's a moment where the main characters discuss a timeline described as "on the order of 50 years." This is still a fairly common phrasing, and in general, people around me generally take it mean "roughly" or "plus or minus a few," which is how one character interprets it. Another character then explains that its actual meaning is, paraphrased, "probably not less than 5 years or more than 500 years." While I had a vague awareness that "on the order of" was not mathematically equivalent to "roughly", I don't remember learning the concept in such a memorable way. Similarly, an order of magnitude are commonly understood as "a lot more than", when they also have a precise mathematical definition. I think that reason we are terrible at estimating the time something will take is that humans struggle to think in terms of timespans that are actually representative of the variance in an estimate, not to mention the fact that as additional variables are introduced, that variance will almost certainly increase (even if the midpoint decreases). I'm not sure of the causal direction here, but our misunderstanding of terms meant to succinctly express "somewhere between" sure doesn't help things. (side note: there's also a discussion about designing a revolutionary organization that really clarified my rudimentary understanding of circuits. The book is truly stunning at times.)