Neatly splicing two threads, a reader offers this:
“Here’s a definition of inflection point that might be more helpful to your
readers: The inflection point is the spot where a thing (political issue,
movement, campaign, etc.) stops increasing its momentum and starts
decreasing its momentum (or vice versa). It is still moving in the same
direction (so it hasn’t turned), but it now looks like it will eventually
stop, rather than continue indefinitely.
“Gay marriage is a political (rather judicial) movement that kept increasing
its momentum with every court case that was filled. The Goodridge decision
was an inflection point (not a turning point) in that it spurred the
Conservative opposition to move on a Constitutional amendment. Gay marriage
is still progressing (going forward) in its judicial implementation
strategy, but it is definitely losing momentum at the present point and may
very well grind to a complete stop.
“For a bunch of conservatives ’standing athwart history yelling, “Stop!”’
the inflection point is a necessary first step in defeating foolhardy
attempts to change the status quo.”
And all without a single diagram!
[Note that since momentum is just mass times velocity, and
acceleration/deceleration are just increasing/decreasing velocity, and
therefore momentum, this is really the same as the non-mathematical
definition I gave — if you ignore relativistic effects…]