One of the things that came up at the last SSC Atlanta meetup was the notion of the Murder Ghandi (read the link for an explanation). It’s easy to think of the whole concept as a good example of slippery slopes, i.e. where the same person faces different incentives over time. However, I think the true point is a bit more lasting than that – and much more useful and interesting.
The “make me 1% less pacifistic” pill does not just change the incentives – it is fundamentally a transformative experience for the pill taker. The person who takes the second pill is not the same as the person who took the first pill. The person is different, not the incentives. This should be explained by mathematical formula.