An independent variable is under your control, like a knob that you can twist. A dependent variable is what results, the output of a system. If you say "y is a function of x" then you're implying that x has free will and y just follows orders.

But it's often convenient --- and mathematically/philosophically powerful --- to flip a relationship around and view master as slave, and vice versa.

So when I hear that running pace inexorably declines by 1% per year of age, I prefer to invert that equation and think: If I go 1% slower then I'm a year younger!

(see also MandatoryInversion (2 Sep 1999), NeedForSpeed (10 Aug 2002), ...)

TopicScience - TopicRunning - TopicHumor - Datetag20030409

(correlates: TwoPerspectives, Asimov on Zoology, LogSlow, ...)