What is logical time?

I tried to find an existing name for this concept, without success. If you know the proper term, please write a comment or contact me.1

To understand what I mean by logical time, let’s pretend it’s 11.59p on Monday night. The clock ticks and turns midnight, and then 12.01a, then eventually 1.33a. Do you think it’s Tuesday morning?

Even though technically it’s Tuesday, most people think it’s still Monday night.2 If you’re out until 2.00a, you’ll tell people, “I was out late last night.” This leads me to sometimes joke that if I promise you something by the end of day, I really mean 4.00a tomorrow.3

But most software I’ve encountered doesn’t really take that into account; if it happened on Tuesday 1.00a, it happened on Tuesday, period.

Naturally, I don’t think that’s acceptable. Logical time embraces the idea that your day ends when you go to sleep, and begins when you wake, not on some arbitrary notion of midnightness.

And thus, my upcoming app treats any activities that happen up to 4.00a as having been done the previous day. The precise time at which we shift from thinking about last night to this morning eludes me, but I suspect 4.00a is, for most people, that transition point.4

But that’s not all.

Normally when you change time zones, your calendar will show events in absolute terms, so if you have an appointment tomorrow at 3.00p PDT in Seattle, and you’re now in New York, your calendar will show that you have an appointment at 6.00p EDT. Most software behaves this way.5

So while accurate, it’s not actually helpful.6 Back when we had paper calendars, we recorded the time of events in terms of the time zone we expected to be in. It’s only useful to have the time of the appointment be displayed in absolute terms when (1) you’re not in your usual time zone, and (2) you’re scheduling an interaction with another party.

It also complicates tracking time. When we travel, we aim to renormalize our body cycles to the new time zone; so that we go to sleep (and wake up) at the same time every day. When I look at my calendar while traveling, it’s a wee bit aggravating to see everything shifted by the time difference; I have to mentally shift the time in my head.

So my app also performs the not-complicated-but-still-kinda-aggravating calculations to make events always show at the same abstract time, wherever you are.

Logical time: time the way you experience it.