It is a common part of moral reasoning to propose hypothetical scenarios.  Whether it is our own Torture v. Specks or the more famous Trolley problem, asking these types of questions helps the participants formalize and understand their moral positions.  Yet one common response to hypothetical scenarios is to challenge some axiom of the problem.  This article is a request that people stop doing that, and an explanation of why this is an error.

First, a brief digression into law, which is frequently taught using hypothetical questioning.  Under the Model Penal Code:

A person acts knowingly with respect to a material element of an offense when:
(i) if the element involves the nature of his conduct or the attendant
circumstances, he is aware that his conduct is of that nature or that such
circumstances exist; and
(ii) if the element involves a result of his conduct, he is aware that it is
practically certain that his conduct will cause such a result.

Hypothetical: If Bob sets fire to a house with Charlie inside, killing Charlie, is Bob guilty of knowing killing of Charlie?  Bob genuinely believes throwing salt over one's shoulder when one sets a building on fire protects all the inhabitants and ensures that they will not be harmed - and did throw salt over his shoulder in this instance.

Let us take it as a given that setting someone on fire is practically certain to kill them.  Nonetheless, Bob did not knowingly kill Charlie because Bob was not aware of the consequence of his action.  Bob had a false belief that prevented him from having the belief required under the MPC to show knowledge.

The obvious response here is that, in practice, the known facts will lead to Bob's conviction of the crime at trial.  This is irrelevant.  Bob will be convicted at trial because the jury will not believe Bob's asserted belief was true.  Unless Bob is insane or mentally deficient, the jury would be right to disbelieve Bob.  But that missed the point of the hypothetical.

The purpose of the hypothetical is to distinguish between one type of mental state and a different type of mental state.  If you don't understand that Bob is innocent of knowing killing if he truly believed that Charlie was safe, then you don't understand the MPC definition of knowing.  Discussion of how mental states are proven at real trials, or whether knowing killing should be the only criminal statute about killing are different topics.  Talking about those topics will not help you understand the MPC definition of knowing.  Talking about those other topics is functionally identical to saying that you don't care about understanding the MPC definition of knowing.

Likewise, people who responds to the Trolley problem by saying that they would call the police are not talking about the moral intuitions that the Trolley problem intends to explore.  There's nothing wrong with you if those problems are not interesting to you.  But fighting the hypothetical by challenging the premises of the scenario is exactly the same as saying, "I don't find this topic interesting for whatever reason, and wish to talk about something I am interested in."

In short, fighting the premises of a hypothetical scenario is changing the topic to focus on something different than topic of conversation intended by the presenter of the hypothetical question.  When changing the topic is appropriate is a different discussion, but it is obtuse to fail to notice that one is changing the subject.

Edit: My thesis "Notice and Justify changing the subject," not "Don't change the subject."