For those of you unfamiliar with the trolley problem, or trolley car problem, Wikipedia has a good basic summation, and I'll give you a bit myself.
Imagine a trolley car, street car, or similar that's suddenly gotten out of control and threatens to kill five people tied up on the track in front of it.
In one scenario, a person can throw a switch to divert the car onto a siding, where it will kill just one tied-up person instead. In the other, the person can push one overweight man onto the tracks in front of the five tied-up people, stopping the train that way.
"Real world" experiments on simulators say people are less likely to do the rational decision in the second case, presumably because it requires them to actively push someone.
Well, first, we could change this. Make them the conductor of the streetcar, in the first scenario, so they'd have to make an active decision to run over either the one person or the five.
A variant on the second alternative says, make the fat man a villain. Maybe people will be more likely to push him, then.
However, the issue of death aside, simulation machines can't get perfect results.
Second, in the real real world, this isn't an issue we're likely to face.
As Sarah Bakewell notes at the New York Times, "trolleyology" is a serious issue that has reached into classes at West Point and many other places.
So, let's study it more realistically.
Here's some much more likely scenarios, in which the issue of death may not be an "aside."
You have $50 for charity. Do you give it to the local food bank, where it will help 10 people, all of whom are likely to live, even without that help, or Oxfam, where it will help 100, some of whom may well die without it?
You have $50 for charity and you're an atheist. Do you give it to Oxfam, if it will help 100, or to a Christian-based group like, say, Feed the Children, if it will help 125 but be accompanied by explicit Christian proselytizing?
You have $50 for charity and you're a conservative Christian. Feed the Children, if it will help 100 with the benefit of being accompanied by explicit Christian proselytizing, or give it to Oxfam, if it will help 125 but without any Christian missionary work?
You have $10,000 for charity and you're a patron of the arts. Do you use most of it for a school in an impoverished neighborhood to hear a classical music performance, or do you use most of it for the nearest area food bank? If the food bank agrees to name a donation program after you, does that influence your decision?
If you're a Cass Sunstein, and you don't like how people respond to some of these issues, should you pay them cash to "nudge" their decisions? If so, how much? Should you pay cash for a nudge rather than directly giving that money to Oxfam or a local food bank?
I encourage professional philosophers to use my few tidbits of thought experiment to do more along the line of developing more realistic takeoffs on the trolleycar scenario. Per Massimo Pigliucci, that's what being a public intellectual is all about.