I can not remember the name of this logical fallacy. The fallacy suggests that when there is a lack of knowledge on a subject it is because, either: a rational answer does not exist, or a answer without any need for proof exists.


  1. "We can't explain why the lamp just moved, therefore it must be supernatural."
  2. In the History Chanel TV programme "Ancient Aliens", the logic "no one can explain it, therefore it must be aliens"

Examples 1 and 2 have subtle differences and might have different names.

  • The first one isn't really a fallacy. The definition of ‘supernatural’ is essentially “attributed to some force beyond scientific understanding” (ODO)—so if science cannot explain it, it is pretty much supernatural by definition.
    – Janus Bahs Jacquet
    Sep 13, 2016 at 15:40
  • Just because a particular group of people can't explain an event, doesn't mean that no one can explain it.
    – Morgoth
    Sep 13, 2016 at 15:43
  • True; but it's not a fallacy if we take “we” to refer to mankind in general and the bulk of scientific understanding that it has accumulated.
    – Janus Bahs Jacquet
    Sep 13, 2016 at 15:44
  • 2
    Ad ignorantiam, appeal to ignorance, we already have a thread about it philosophy.stackexchange.com/questions/32257/…
    – Conifold
    Sep 13, 2016 at 19:55

2 Answers 2


You may be thinking of the Argument from Ignorance fallacy:

An appeal to ignorance is an argument for or against a proposition on the basis of a lack of evidence against or for it. If there is positive evidence for the conclusion, then of course we have other reasons for accepting it, but a lack of evidence by itself is no evidence.



It sounds like Fallacy of Presumption.

There are situations of presumptions such as

  • insufficient/incomplete logic coverage; missing premise
  • aliasing/ambiguity
  • latent conditions (presuming a previous regimen still holds)
  • circular dependency/complexity

You should be able to Google search on it.

1. Fallacy of presumption due to missing premise.

Let's say in a certain city, people there have two attributes

  • either rich or poor
  • either famous or mundane

Then an alien UFO ship (UFO would be an oxymoron, when the aliens identify themselves) captures the city and issues the edict

  • Everyone will have a place in the new city that we will rebuild
  • Only the rich and famous will be allowed to roam the city freely.
  • Whereas the poor and mundane would be confined indenture.

Then the people start to wonder. The new rulers say everyone, but what about

  • the rich and mundane
  • the poor and famous?

Then an alien leader responded with the presumption

  • all who are rich are famous, that is why you earthlings say rich & famous.
  • there is no such thing as poor and famous, because we have not witnessed such in the TV shows your planet's broadcast.

2. Let's look at another case of missing premise

  • pigs eat corn
  • Anna eats corn
  • Anna is a pig

3. Fallacy of aliasing.

Different concepts sharing the same name/word.

  • The king said, all houses should be encased with stones.
  • Should the house of Israel and Judah also be encased with stones?
  • You will be saved by faith alone, preached the pastor.
  • Then George yelled, Amen! I have faith in the lottery ticket I just bought, praise the lord!

4. Fallacy of complexity and circular dependency

Homosexuality is wrong.

  • It is wrong because it is unacceptable
  • It is unacceptable because it violates norms
  • Violating norms is wrong


Not the answer you're looking for? Browse other questions tagged .