I am operating with the Principle of Double Effect (PDE). — Gregory of the Beard of Ockham

Would you push a fat guy off a bridge to stop a train that was going to kill 5 people? If not then how exactly is this different from flicking a switch?

Harvesting the organs of someone to save 10 lives assuming there is no other availble means to save these 10 lives?

How about being in a position where you push someone onto the track to stop every other human life on the planet being snuffed out? — I like sushi

Is that even a possible situation? I believe morality is about how we should act in actual or possible situations. If you think this is a possible situation, please explain how it would work.

Would you push a fat guy off a bridge to stop a train that was going to kill 5 people? If not then how exactly is this different from flicking a switch? — I like sushi

No. Assuming that the fat guy's body is meant to stop or slow down the train, it is different because it violates the condition that the bad effect must not be the means of achieving the good effect.

Harvesting the organs of someone to save 10 lives assuming there is no other availble means to save these 10 lives? — I like sushi

If you're asking me if I would do this or recommend doing it, then, assuming that means killing the donor, the answer is no.

Is that even a possible situation? — Gregory of the Beard of Ockham

Yes. You just need a very long train track :D Possible worlds theory allows this.

"2. The agent may not positively will the bad effect but may permit it. If he could attain the good effect without the bad effect he should do so. The bad effect is sometimes said to be indirectly voluntary." — Gregory of the Beard of Ockham

It is permitted to push the guy to save 5 lives. If no for you how about 1,000,000 lives.

DDE is not clear cut.

And in Stanford Encyclo:

According to the principle of double effect, sometimes it is permissible to cause a harm as an unintended and merely foreseen side effect (or “double effect”) of bringing about a good result even though it would not be permissible to cause such a harm as a means to bringing about the same good end.

The nuance comes down to what is considered a 'side effect'.

Is that even a possible situation? — Gregory of the Beard of Ockham

Yes. You just need a very long train track :D Possible worlds theory allows this. — I like sushi

Ah, when you said earlier "to stop every other human life on the planet being snuffed out" I thought you meant the other 8 billion lives on earth in this actual world that we live in. But if you want to bring in possible worlds ...

It's easy to imagine a very long train track. Conceiving of this possible world coherently, in a way that benefits your case, is harder.

A. We could have a possible world with only six people, five of whom will be killed if the trolley is not diverted. Maybe. In a world with six rational inhabitants, is it really possible that their civilization developed highly enough to build trains? Okay, maybe their ancestors built the trains, and these six are just a remnant left over after some horrible disaster. But in any case, we are back down to the same numbers as before, so the pressure to "save 8 billion people" does not apply here.

B. Or a world with 8 billion people, all standing on a very long train track, and all lacking the sense to get out of the way of a massive, rapidly moving object. With the laws of physics in the actual world, this train would begin plowing into the people, but then it would slow down and halt, because of friction and conservation of momentum (or maybe of energy). So in this possible world, we do not have those physical laws. But if there is no friction, trains would not work, and people would not have built them. In fact, without friction and conservation law(s), human beings could not exist. If there is any rational life in such a world, their natures would be so radically different from ours that perhaps our moral laws would not apply to them.

C. Of course, there are many other possible worlds, but it is up to you to describe one, if you want to, in sufficient detail that pushing someone onto a track to save all other human life would make sense.

That's all I have time to say for tonight.

These morality thought experiments have variations to challenge one's answers to measure how consistent one can be. To me this is the only worthy point for spending time on these simulations.

The trolley, the bridge, organ transplant have layers of conditions such as, what if the 5 individuals in the tracks are criminals and the one person to sacrifice is a good man with family. Or what if the one individual is a family member.
The utilitarian answer will always choose the number of people saved, I suppose.

But, as I have always answered it based on virtue ethics-- maybe even deontology-- I will switch back and forth to stay true to the moral principles I follow.

One curious thing about these thought experiments is, they don't challenge you by asking, will you lay down on the train tracks to save 5 people, or let the doctor harvest your organs to save 10 people. I would answer, no. I would not give up my life except for loved ones.