Paradoxical arithmetic

One of my students wrote a curious piece last week on Incongruent Arithmetic:

I know someone facing a long-overdue and unfortunate divorce. A friend told her to try to think of it as “addition by subtraction.” Gaining more life spirit, happiness, etc. by the removal of the negative energy of the spouse etc.

And this equation works in the reverse too.  I can subtract from my life by adding the "wrong" things.  As I read through the post, I could see a lot of parallels in my thinking about curing Infoluenza and the general question of Personal Knowledge Management.

This is strongly related to the ideas I've latched onto of "sharpening the saw" (Covey) or the tool box.  To keep things humming in my life, I need to have the tools appropriate to my work.  I need to keep those tools in proper working order, tossing the ones that are no longer serviceable and examining new tools that might work better.