Argumentum ad baculum

An argumentum ad baculum (Latin: "argument to the stick") is a logical fallacy in which the arguer threatens their debate opponent with real or threatened violent or nonviolent coercion.

As with the appeal to bribery, it is the offer of a pleasant consequence if you go along with the argument.

The fallacy is an appeal to fear, an argument from consequences, and an informal fallacy.

Alternate names

 * appeal to force
 * appeal to power
 * appeal to bribery

Form
The argument takes this form:
 * Accepting X leads to action Y against me.
 * I do not want action Y to occur to me.
 * Therefore, X is not true / not false.

Y could be anything from torture to the loss of a potential bribe, as long as it's motivational and tied to acceptance of a proposition.

Legitimate use
As the argumentum ad baculum is an appeal to consequences, it's not fallacious if the argument is based on avoiding consequences rather than any truth value (such as countering epistemological nihilism):

This applies even if the cause of the punishment is itself unjust. Thus, an argument against trying to escape slavery (you will be whipped if you attempt to escape) might be a valid reason to not escape slavery, even if slavery is a moral abomination and illegal in the place to which one escapes (Canada).

Explanation
The danger in holding a premise is irrelevant to the truth of that premise. This argument doesn't make any statement as to whether X is right or wrong, or whether punishment Y should follow action X, only that it's probably not something you want to do.

Examples

 * 1) If I don't think the boss is nice, I will be fired.
 * 2) I don't want to be fired.
 * 3) Therefore, I will think the boss is nice.

Perhaps the most simple example would be:
 * Believe what I say, or I will hit you.

Spanish Inquisition
A modified form of the argument was otherwise known as the Inquisitorial Question, and took this form:
 * If person A denies being a heretic, then we will torture A.
 * Therefore, A is a heretic.

It proved very useful for getting almost all the Inquisition's targets to admit they were heretics. It may also have been effective because nobody expected it.

Nothing to do with
The actual in animal anatomy. As such, this is not "Argument to the penis bone", especially since humans lack said bone.