argumentum ad consequentiam
(also known as: appeal to consequences of a belief, argument to the consequences, argument from [the] consequences)
Description: Concluding that an idea or proposition is true or false because the consequences of it being true or false are desirable or undesirable. The fallacy lies in the fact that the desirability is not related to the truth value of the idea or proposition. This comes in two forms: the positive and negative.
X is true because if people did not accept X as being true then there would be negative consequences.
X is false because if people did not accept X as being false, then there would be negative consequences.
X is true because accepting that X is true has positive consequences.
X is false because accepting that X is false has positive consequences.
If there is objective morality, then good moral behavior will be rewarded after death. I want to be rewarded; therefore, morality must be objective.
If there is no objective morality, then all the bad people will not be punished for their bad behavior after death. I don’t like that; therefore, morality must be objective.
Explanation: The fact that one wants to be rewarded, or wants other people to suffer, says nothing to the truth claim of objective morality. These examples are also begging the question that there is life after death.
Exception: If it is understood by both parties that an argument is not being made, rather it is a warning based on possibilities, and the person issuing the warning acknowledges it is not evidence for the claim, then there is no fallacy. The problem is virtually every such warning has an implied argument, so it is very debatable what is fallacious or not.
Tip: Realize that you can deal with reality, no matter what that reality turns out to be. You don’t need to hide from it—face it and embrace it.