Language Log readers may appreciate the following classic example of writing in technical terms from the perspective of the technician or engineer rather than from a standpoint that would seem useful to the customer or reader. I was engaged in reserving a rental car on the web, and got the date syntax wrong. Instead of having one of those little click-on-the-calendar widgets, the site required entry of the date of the reservation in a blank box using a strict syntax that it did not explain until the reservation failed and an error message was displayed. By strict syntax I mean (i) slash must be used as separator (continuous numbers will not work), (ii) day must be before month (American month-day-year syntax will not work), and (iii) the date must be four digits (two-digit year indications won't work). I'm not worried about having to know the date syntax of the culture I'm in; I can deal with that. And although the 4-digit year is a bit crazy (since time travel is impossible, the first two digits will be 2 and 0 for all reservations for the next 92 years, so they are not carrying much information), that piece of programming stupidness is not my concern here. The classic bit was the error message that popped up in red:
Please select a valid pick up date (DD/MM/YYYY) greater than today.
Have you ever said "I could do lunch any day next week greater than Tuesday"? Or "It would be helpful if you could deliver it greater than the 27th"? Or "I'm younger than my wife because my birthday is eight days greater than hers"? Of course you haven't.
Only for the utter benighted nerd is the greater-than relation, as used in integer mathematics, defined on dates. Sure, in Unix date program date-setting notation, today is 0624 and tomorrow is 0625, so the sort -n command sorts them in that order. A nerd will keep his records for June 2008 in a file called 200806 and the ones for July in 200807 so that the ls program shows everything in chronological order. These facts might cause the mathematically inclined to think of dates as integers so that one can be greater than another. But ordinary people trying to rent cars say "later than" or "after"; they don't say or think "greater than".
And by the way, let me just point out (if I may risk using nerdery to fight nerdery) that under British day-month-year syntax, the greater-than relation will not work correctly: the last day of this month will be 30062008 and the follow day will be 01072008, and 01072008 (= 1,072,008) is not greater than 30062008 (= 30,062,008), so sort -n would not sort the dates correctly into chronological order if they were kept in that form. The same holds if the slashes are retained rather than erased.
The problem I am pointing to, however, is not about web programming or sorting technicalities. It is a simple problem that afflicts us all: people with any kind of technical knowledge of a domain tend to get hopelessly (and unwittingly) stuck in a frame of reference that relates to their view of the issue, and their trade's technical parlance, not that of the ordinary humans with whom they so signally fail to engage. I have written about this before — in Per bus per journey, for example, and probably on several other occasions. The phenomenon — we could call it nerdview — is widespread.