Risk analysis. The risk is a function of the likelihood of the occurrence of an event in relation to the degree of harm threatened.
If the likelihood is low that person A is in possession of information that could avoid the occurrence of a catastrophic event then there would be no question that the use of coercive interrogation would be inappropriate and immoral.
The ethical problem arises when you have high confidence that person B is in possession of information that could avoid the occurrence of a catastrophic event.
Here's where the calculus becomes terrible. What if person B is in possession of information that the operator is confident will result in the deliverance of an innocent person from otherwise certain death. Most would say, our values are such that the greater good is served by not using extremely coercive interrogation to save the innocent person. This would also be the case if 10 innocent persons were at risk.
But, what if person B were in possession of information the if secured within time (x) would avoid the risk of harm which is the release in a major international airport of a highly contagious, airborne virus worse than the Spanish Flu? The risk is a lethal pandemic that could reduce the world's population by a non trivial percentage.
What then? What is the moral choice?
The answer is clear. If you weigh the risk of harm (death of scores of millions of people), against the likelihood of the occurrence of the risk (100% unless the information is obtained), and a high likelihood (>50%) that person B is in possession of the information which if obtained would avoid the occurrence of harm. Turn on the faucet.
If it is just a matter of numbers, then why is it ethical not to use coercive interrogation in order to save a single innocent life?
