There is a great book on this topic by Jeff Schmidt called Disciplined Minds: http://www.amazon.com/Disciplined-Minds-Critical-Professiona...

Here's a review: http://www.uow.edu.au/~bmartin/pubs/01BRrt.html

Earning a PhD certainly requires independent thought and action, but those are directed towards goals imposed by someone else, typically an adviser or one's committee, and the typical grad student rarely questions those goals.

This capacity for creative work in pursuit of others' ends is exactly why Rachel says PhDs are such valuable minions.

The book "Disciplined Minds" [1] makes this point in a radical way. I didn't agree with everything it said, but its point is that higher education selects for people willing to jump through arbitrary hoops for nebulous returns, and that that conformism is valuable to employers.

[1] http://www.amazon.com/Disciplined-Minds-Critical-Professiona...

Disciplined Minds by Jeff Schmidt is an excellent book on this topic: http://www.amazon.com/gp/product/0742516857

There's a review of it here: http://disciplinedminds.tripod.com/higher-education-review.h...