This is something I'm sure most people have heard before, but I'm curious how a discussion might go. I'll bring up three moral dilemmas which are essentially the same, in a way, but which people tend to have different answers to. The thing to note is that you'll probably have a different answer to the first and the last. If this is true for you, do you have a rational reason for the different choice, or is your decision due to a feeling? What is the 'right' thing to do, and why? Feel free to bring up your own moral dilemmas.

The Trolley
You find yourself on a trolley headed down a track. You see 5 unaware people in front of you on the track which the trolley is about to hit and kill. You may choose to pull a lever which will send the trolley down a different track, which one hiker is walking across. If you choose to hit the lever, you'll be killing the hiker, who was minding his own business, to save the other 5 people. Do you pull the lever?

The Bridge
You are standing on a bridge above a trolley in a similar situation to the last, except there is no one in the trolley now and it will definitely hit the 5 people. A stranger is standing next to you. You know, somehow, that if you push this person off the bridge, they will land on the track and slow down the trolley enough to save everyone else. Of course this will kill the person. Do you push him off?

The Patients
You are a doctor with 5 patients. Each one is suffering from the failure of a vital organ, and there have been no matches found for transplants. All 5 patients are surely going to die. A 6th patient comes in for a regular check-up, and you find they are completely healthy. Also, during your analysis, you find that his organs happen to be perfect matches for your 5 dying patients. Do you murder the healthy person to save the other 5?

Does your answer to any of these questions change if you would be saving less or more people than 5? What about 2 people? What about 10,000?