Velocity blindness

[gfish]

When I was researching clock design extensively last year, I had an odd linguistic revelation. All my life I'd been saying a clock was "fast" or "slow" to indicate it was ahead or behind the correct time. This purely meant a fixed offset -- a clock was 5 minutes fast, and would still be 5 minutes fast next week. In fact, if a clock really WAS fast, getting further and further ahead I'd have to explicitly specify that. It was a sloppy use of "fast", but, eh, natural language is full of that. I never really thought about it. It wasn't until getting into the history of clocks that I realized this hadn't always been an idiosyncratic phrasing. It used to be quite literal. Clocks used to suck, even very expensive ones. If your clock was fast, it would be noticeably gaining time day after day. We live in an era of incredibly cheap, incredibly accurate clocks. Even the cheapest quartz wristwatch might only gain a few seconds over an entire year, a level accuracy that used to only be found in the best observatory regulators. So while the immediate observation is the same (a clock is 5 minutes ahead), the underlying condition is completely different. It's like seeing a plane taking off over a continental plate boundary and thinking they both have the same velocity since they're the same distance away from you. We take it so granted that clocks are (for >99.99% of human activity) perfectly accurate that we have taken the indefinite integral of a common figure of speech without even realizing it. That's pretty cool. I can't think of any other examples of that happening.

Comments

[neuro42.livejournal.com]

The latter, yes, but I consider that a flawed backformation.

The majority of people know set their clocks 'ahead', not fast.

I suppose I've never conducted a poll, but I can't imagine anyone I know thinking that a clock that is fast is not going to get further ahead over time, although it might easily be on the scale of minutes per year and not minutes per week.

[memegarden.livejournal.com]

If I hear someone say "that clock is five minutes fast", I assume it's five minutes ahead but reasonably accurate in tracking the passage of time. This is in fact true for the clock in my hallway, which has been about five minutes ahead for the past year or so since it was last set, and I just haven't bothered to reset it correctly.

If someone meant that the clock actually ran faster than time does, I'd expect to hear something like "that clock runs a little fast" rather than "is five minutes fast".

[neuro42.livejournal.com]

why on earth did whoever went to the trouble of setting the clock set it wrong in the first place? that's what I don't get.

[gfish.livejournal.com]

I know this will come as a surprise, but not everyone sets their clocks from tier 1 reference signals.

[memegarden.livejournal.com]

That would be me, I think. I probably just looked at another clock and then went up and set it, and took longer than I thought I had. Having a clock there that's five minutes wrong has been immensely more useful than not having one. And others in the house have noticed it's five minutes off, and not bothered to reset it themselves, so I think we're all pretty much on the same page on that.

[neuro42.livejournal.com]

I suppose I have to admit that there are a few people in the world still who don't have an ntp client in their pants, but the idea of bothering to set a clock but not bothering to set it correctly makes my brain hurt. :)