On the Nature of Incremental Change

I've recently seen photographs of several friends and acquaintances I haven't seen, in person, in at least ten years.  (mostly a result of certain social-networking sites)  Clicking through their photos, I'm struck by how much they look like grownups.  I'm not saying they haven't aged well - it's just that they don't look like they're in high school or college anymore.  My mental image of them hasn't changed since I last saw them, but obviously, we've all gotten a decade older.   Same thing happens with my cousins - and they're young, which amplifies the phenomenon - my mental images of them are as toddlers, but they're in upper elementary school now. Anyhow, when I look at pictures of myself, I don't marvel at how different I appear from ten, fifteen years ago. I mean, I know I've changed, but I've been present for the changes.  It isn't until I see a photo from 1997 and I can't help but notice how much younger I appear.  And that's not entirely true either.  When I look at that photo from 1997, what catches my eye is how much younger the other people appear.  Only then do I think, "oh, yeah, me too".

I don't mean for this post to come across as a lament of the aging process - I don't have a problem with growing older.  What's interesting is my tendency to not age-progress individuals, and how surprised I am when I see that they're adults now.  It's clearly a function of how often I see someone.  Incremental change on the order of days or months is significantly smaller (and less noticeable) than that on the scale of years, even decades.

The shift of plates goes unnoticed until a dramatic event.

There's another strange time phenomenon going on in my head. I occasionally manage to neglect a four-year chunk of my life, the California Years.  From time to time, I simply forget we lived there.  I remember the people and the places, but sometimes, when I'm going through my mental timeline, I find I just close the gap between college and Florida.  This happened most noticeably the year I spent advising college-bound high-school seniors.  The more I talked about college and thought about what it was like to go off to college, the time gap between now and then started to shrink; when I caught myself, it was with marvel that there was a chunk of four years (and even a couple years here) that I just glazed right over as though they were insignificant.  Which they weren't.

Time is a transparent film, stretching and shrinking.

I was asked recently, on the occasion of my ninth wedding anniversary, how my marriage had changed over time.   It was a more difficult question than I expected it to be.   I know there has been change, but I can't articulate it, and I certainly can't divorce it from our own individual changes.  It's a kind of relative-motion frame-of-reference problem, because our relationships evolve as we are changing, too.

A person walks at a speed of 2 m/s relative to a moving sidewalk. If the sidewalk is moving at 3 m/s relative to the ground, what is the person's velocity relative to an outside observer?

I couldn't answer her - there seem to be too many variables to come up with a meaningful answer, relative to an outside observer.

[Originally drafted 25 July 2008]