this was covered here: http://lesswrong.com/lw/65/money_the_unit_of_caring/
“If the soup kitchen needed a lawyer, and the lawyer donated a large contiguous high-priority block of lawyering, then that sort of volunteering makes sense—that’s the same specialized capability the lawyer ordinarily trades for money. But “volunteering” just one hour of legal work, constantly delayed, spread across three weeks in casual minutes between other jobs? This is not the way something gets done when anyone actually cares about it, or to state it near-equivalently, when money is involved.”
Did the next few posts Luke mentions would be about empathic metaethics ever get written? I don’t see them anywhere.