Appeal to Ignorance

  This fallacy occurs when someone asserts a proposition as either true or false, solely because of insufficient proof.  The structure of the fallacy looks like this:

Why appealing to ignorance is fallacious:

Reality is independent of the human experience.

“There has been no burglar in my home, because nothing is missing.”

  At first glance this seems perfectly reasonable. However, if they venture upstairs and see a broken window, muddy footprints, and an open safe, the probability of burglary is quite high. High enough to supersede the inability to find the missing item.

  Herein lies a crux of this appeal – that reality is independent of the human experience. Just because we lack evidence of something does not conclusively deem it true or false. This is exemplified in the following three examples:

• An exterminator sees no mouse droppings, and therefor concludes that all the mice are gone. However a week later the client calls back extremely angry because she saw a mouse in her kitchen.

• A man believes he is perfectly healthy. After a routine check-up, the general practitioner discovers a melanomas growth on the man's back. Reality did not change in that instant, but the man's experience of reality was flipped upside down.

• A thousand years ago, many European scholars believed the earth was flat, because there was no evidence to the contrary. Today, satellite pictures show us that Earth has been round all along.

As you can see, insufficient proof does not change reality.

Things can be unknown or unknowable.

“There is no proof of God, therefor there is no God”

  This statement seems pretty reasonable, but neglects the more appropriate response of agnosticism. People who commit an appeal to ignorance often hinge their belief on a false dichotomy – that things must be either true or false. Whereas a true thing can never be disproved, the opposite idea, that 'an unproven thing is false' is invalid logic. This is because things are not solely true of false, but can also be unknown or unknowable. For example an agnostic atheist does not believe in any deity, but does not deny the possibility.

Dealing with this appeal in our daily lives:

People wrongly misplace the burden of proof.

“Prove me wrong!” or “There's no evidence that I'm wrong”

  When a debater tries to persuade an argument in this way, they are misplacing the burden of proof. Remember the adage “An extraordinary claim requires extraordinary evidence”? When the debater makes a claim, that claim requires proof. Merely telling the other side of the argument that they can't disprove it, is not proof - it is misplacing the burden of proof. For example:

Jose: “Mozart is better than Beethoven”

Amy: “No way, Jose!”

Jose: “Well prove me wrong!”

Amy “Um...”

Jose: “Aha! See, you can't prove me wrong, so I must be right!”

  Amy has provided no evidence that Mozart is not better than Beethoven. This does not render Jose's claim true. For Jose's claim to hold truth, he will have to support it with his own reasoning as the burden of proof remains on him and his bold claim. A lack of evidence by itself is no evidence.

But we are innocent until proven guilty!

  Not everywhere! The presumption of innocence stems from Latin routes (ei incumbit probatio qui dicit, non qui negat, Literally: the burden of proof rests on who asserts, not on who denies.) In Stalinist Russia you were guilty until proven innocent. Remember that the assumption of innocence is a practical, not a logical, process.

Appeal to Emotion

Appeal to Fear

Appeal to Tradition

Appeal to Popularity

Appeal to Force

Appeal to Belief