There is an old story about an old man who has to cross a desert.
He has two enemies.
One night the first enemy slips into his tent, and puts poison in his water bottle. Later the same night, the second enemy, not knowing of this, slips into his tent and puts a tiny puncture into the bottle.
In the morning, the man sets off across the desert; when the time comes to drink water, there is nothing in the bottle. As a consequence, he dies from thirst.
Who murdered him?
The defence lawyer of the first man argues that, admittedly, his client attempted to poison the man. But he failed; the victim took no poison.
The defence lawyer of the second man argues: it’s true that my client attempted to deprive the old man of water. But he failed; all he did was deprive him of the poison, and you cannot murder someone by doing that.
How do we solve this ethical dilemma?