Morality and Trolleys

In a recent discussion with a philosophy Professor who is teaching a course on "God and Morality" posed the following scenario to me.

A trolley is running out of control down a track. In its path are 5 people who have been tied to the track by a mad philosopher. Fortunately, you can flip a switch which will lead the trolley down a different track. Unfortunately, there is a single person tied to that track. Should you flip the switch?

This is not a recent problem though it is still currently studied, though it occurs to me that the answer is obvious. However, this Professor explains that there is a good amount of discussion on what the moral view is. Most people say that it is permissible to flip the switch and therefore the better option (opposed to letting it happen).

The Professor relates a related scenario

A trolley is hurtling down a track towards five people. You are on a bridge under which it will pass, and you can stop it by dropping a heavy weight in front of it. As it happens, there is a very fat man next to you - your only way to stop the trolley is to push him over the bridge and onto the track, killing him to save five. Should you proceed?

The more P.C. scenario involves a man with a backpack. According to the Professor most people make a moral distinction between actively causing the death of the fat man and flipping the switch in the first scenario. Some even say that it is required that one flip the switch and only permissible to use the fat man to save those five people.

A former classmate of this Professor is studying the brain waves of people when these scenarios are posed to them. Apparently the brain wave scan (A CAT scan?)shows that the emotions are aroused and therefore, this doctor concludes morality is lead by emotions.

This situation is qualitatively different than the idea found in Bava Metzia 62a and Sanhedrin 74a where there is a discussion of מאי חזית which prevents one from murdering himself to save the life of one's friend. Rashi does bring up an idea that may shed some light on our situation; in Sanhedrin 74a he states that one does not know the importance of another's life and is therefore unable to 'play God' and decide.

מי יודע שיהא דמך חביב ונאה ליוצרך יותר מדם חבירך

Halachically, in our case, it is a clear Shev v'al Tashev that one cannot cause the death of another to prevent the death of another. In both of these scenarios one must turn away and let God's plan take course.