Yesterday, in a moment of distraction, I put the wrong password into my office smartcard three times, causing it to lock up.

There are two ways of sorting that out. One is to go cap in hand to the IT support people, and wait while they do mysterious things on phone and screen, feeling mildly idiotic, despite their friendly charm.

The other is to go into a special user ID which loads a programme to reset the password. It’s very easy. All you have to do is remember the answers to three questions you gave several years ago when the thing was set up in the first place. Which, of course, is potentially not very easy at all.

Three questions. Favourite teacher. Pet’s name. Favourite singer.

This wasn’t going to work. I could argue with myself for the rest of the day what the right answer to any of them should be, and still not reach agreement.

I stared at the screen for a while. Then the penny dropped. The question wasn’t:

What is the right answer?

It wasn’t even:

What might you have thought the right answer was a few years ago?

It was actually:

How would you have answered them to give your future self the best chance of answering them?

Armed with that insight, the rest was easy. I know how my past self thinks (if less often what he thought). Three correct answers at the first attempt.

Back to work.