It MUST Be True!!!

Today’s Logical Fallacy is called “Appeal to Consequence of a Belief”.  It has the following format:

1) X is true because if people did not accept X as being true then there would be negative consequences.

2) X is false because if people did not accept X as being false, then there would be negative consequences.

3) X is true because accepting that X is true has positive consequences.

4) X is false because accepting that X is false has positive consequences.

Examples of this belief set look something like this:

1) God MUST be real! If God isn’t real then no one would know the difference between right and wrong! The world would be a terrible place!

2) Bad things like I see on the news won’t happen in our neighborhood. If I believed things like that could happen here, I would be too afraid to go anywhere or do anything.

3) I believe that if I am a good person and follow the teachings of the church I will go to Heaven.

4)I agree that I have no science-based proof for the existence of fairies and dragons. However I REALLY want to believe in those things. So it MUST be true!!

This line of “reasoning” is a fallacy because the supposed consequences of the beliefs have no impact on whether the stated belief is true or false. For instance, say I tell you I believe with all my heart that there is an invisible pink Unicorn in my backyard that only eats the purple flowers in my garden. If the Unicorn doesn’t really exist then I would be broken hearted and very depressed. Since I would be SO broken-hearted, the Unicorn MUST exist.

It’s pretty obvious that using feelings and emotions to justify a line of reasoning  isn’t useful in a logical argument. Also, the consequences in question are consequences that stem from belief.

It is important to distinguish between a rational reason to believe (RRB) something (evidence) to be true and a prudential (motivational) reason to believe. 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.



  1. blissbait said,

    October 8, 2009 at 5:54 pm

    i do believe you
    but got a ‘D’ in math class
    Xes frighten me!

    I had to skip a bit cause my brain SCREAMS at X stuff, but dove back in on the dragon line and had a great laugh. I’m taking my mathless self away now. Thanks and Cheers! 🙂

  2. October 8, 2009 at 6:41 pm

    LOL! Don’t fear the X’s here. These are friendly little guys. They LIKE you! Really! They only represent an idea, person or a topic. I promise that there’s no math involved with these particular X’s.

    • blissbait said,

      October 9, 2009 at 2:51 am

      whew! 🙂

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