AR Philosophy > Debating AR > Logical Fallacies - AR
Appeal to Consequences of a Belief

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Includes: Wishful Thinking, Appeal to Consequences (argumentum ad consequentiam)


The author points to the disagreeable consequences of holding a particular belief in order to show that this belief is false. The Appeal to the Consequences of a Belief is a fallacy that comes in the following patterns:

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.
I wish that X were true, therefore X is true. This is known as Wishful Thinking.
I wish that X were false, therefore X is false. This is known as Wishful Thinking.

This line of "reasoning" is fallacious because the consequences of a belief have no bearing on whether the belief is true or false. For example, if someone were to say "If sixteen-headed purple unicorns don't exist, then I would be miserable, so they must exist" it would be clear that this would not be a good line of reasoning. It is important to note that the consequences in question are the consequences that stem from the belief. It is important to distinguish between a rational reason to believe (RRB) (evidence) and a prudential reason to believe (PRB) (motivation). A RRB is evidence that objectively and logically supports the claim. A PRB is a reason to accept the belief because of some external factor (such as fear, a threat, or a benefit or harm that may stem from the belief) that is relevant to what a person values but is not relevant to the truth or falsity of the claim.

The nature of the fallacy is especially clear in the case of Wishful thinking. Obviously, merely wishing that something is true does not make it true. This fallacy differs from the Appeal to Belief fallacy in that the Appeal to Belief involves taking a claim that most people believe that X is true to be evidence for X being true.

Wishful thinking is the formation of beliefs and making decisions according to what might be pleasing to imagine instead of by appealing to evidence or rationality.


"God must exist! If God did not exist, then all basis for morality would be lost and the world would be a horrible place!"

"It can never happen to me. If I believed it could, I could never sleep soundly at night."

"I don't think that there will be a nuclear war. If I believed that, I wouldn't be able to get up in the morning. I mean, how depressing."

"I acknowledge that I have no argument for the existence of God. However, I have a great desire for God to exist and for there to be an afterlife. Therefore I accept that God exists."

You can't agree that evolution is true, because if it were, then we would be no better than monkeys and apes.

You must believe in God, for otherwise life would have no meaning. (Perhaps, but it is equally possible that since life has no meaning that God does not exist.)

You can't agree that pigs have rights, because if it were true, then we would be no better than them.


Identify the consequences to and argue that what we want to be the case does not affect what is in fact the case.

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