A second experiment developed this idea and showed further that an
action is most morally condemnable when personal force and intention
co-occur. Students judged as most morally unacceptable a situation in
which Joe deliberately pushed a victim off a bridge so that he could
reach a switch to save five others. By contrast, if the victim was
knocked off the bridge accidentally so Joe could reach the switch, or
if Joe killed him by diverting a trolley with a switch, then the
students' moral judgements were not so harsh.
something special happens when intention and personal force co-occur,"
the researchers said. This prompts many further questions, such as what
counts as personal force. "Must it be continuous (as in pushing), or
may it be ballistic (as in throwing)?" the researchers asked. "Is
pulling the same as pushing?"
Here is more.