Slate reprints a Financial Times piece on self-tracking, using the recent Quantified Self conference as a jumping-off point to look at the movement more generally. For anyone who's not familiar with it, the article offers a good introduction to the phenomenon, and the spirit behind it:

Moving in the technology circles of New York and Silicon Valley, engineers and entrepreneurs have begun applying a tenet of the computer business to their personal health: "One cannot change or control that which one cannot measure."

Much as an engineer will analyze data and tweak specifications in order to optimize a software program, people are ­collecting and correlating data on the "inputs and outputs" of their bodies to optimize physical and mental performance.

"We like to hack hardware and software, why not hack our bodies?" says Tim Chang, a self-quantifier and Silicon Valley investor who is backing the development of several self-tracking gadgets.

Indeed, why not give yourself an "upgrade," says Dave Asprey, a "bio-hacker" who takes self-quantification to the extreme of self-experimentation. He claims to have shaved 20 years off his biochemistry and increased his IQ by as much as 40 points through "smart pills", diet and biology-enhancing gadgets.

"I've rewired my brain," he says.

I like this quote because it's highlights the somewhat geeky quality of the movement, and the tendency to think of the body as a piece of hardware. (Asprey's assumption that we can "rewire" the brain in directed ways that don't mainly involve things like learning new languages– in other words, the indirect old-fashioned way, through activities, but the new-fangled way, through drugs and so forth– is particularly revealing. Though we often use the term brain when we mean mind, but in this case I suspect the choice is perfectly accurate.)

I'm as big a believer in the virtues of self-tracking as anyone (it was critical for my weight loss, and self-experimentation is one foundation of my contemplative computing work). But as the author notes toward the end of the piece, "Nobody has yet measured the full impact of so fully measuring their lives." More generally, though, thinking about the human body as a piece of hardware leads you to make the kinds of mistakes that Jaron Lanier warns us about in You Are Not a Gadget: the accidental degredation of human abilities through comparison to computers. For it to go mainstream, and to do more good than harm, we need a more human, or humane, version of self-tracking and self-experimentation.