Your Money – Assessing the Damage Caused by Your Card Rewards – NYTimes.com:
“The marginal effect of my individual use… simply won’t impact the larger outcome,” [Dave Hanson, a Spokane, Wash., resident, [who] studied philosophy in graduate school at the University of Chicago and taught applied ethics at Gonzaga University], said. “The assumption that we ought to act in a way that we wish all of us would act ignores the fact that there is no mechanism by which we can ensure that we will all act that way. And we won’t.”