On the other hand, it is only in the last couple of centuries – not long enough to have any evolutionary significance – that we have been able to harm anyone by throwing a switch that diverts a train. Hence the thought of doing it does not elicit the same emotional response as pushing someone off a bridge.
为了应对这样的情况，我们发展出一套即时的、以情感为基础的直觉反应，专门针对施加于他人的人身暴力。将陌生人推下天桥的念头会引起这样的反应。而在另一方面，仅仅是在过去的两百年里—时间短得毫无进化意义—我们才能够通过扳道岔而加害于人。因此这样做的念头不会引发如将某人推下天桥那样的情感反应。