Argument from incredulity, also known as personal incredulity fallacy, is a logical fallacy in which someone concludes that something must not be true (or false) since they cannot believe or imagine it being true (or false).
This type of fallacious move is frequently used in debates over science and religion when certain theories and claims differ from our own deeply held beliefs.
It belongs into the category of informal fallacies, and is a form of appeal to ignorance.
The fallacy of argument from incredulity occurs when someone asserts that because they can’t believe or imagine something being true, it must be false, or conversely, something must be true since they can’t imagine how it could be false.
The person committing this fallacy presumes that the truthfulness of the phenomenon or concept in question should be relatively easy for them to understand or imagine. As such, this fallacy is frequently used in attempts to discredit ideas and propositions that one disagrees with.
This argument can take either one of the following logical forms:
- I can’t imagine how X could be true.
- Therefore, X is false.
- I can’t imagine how X could be false.
- Therefore, X is true.
An example of argument from incredulity would be:
- “The claim that life evolved from bacteria to humans doesn’t make any sense to me, so the theory of evolution must be false”.
Here, he or she simply refuses to believe that the theory of evolution could be true since they are unable to understand it. This line of reasoning is fallacious because it is not backed by real evidence.
- “I simply can’t believe that we landed a man on the moon in the 1960s; how could they travel such a distance with relatively poor technology, and return back to earth unharmed?”
- “I cannot see how the universe would not have a creator, especially when you consider how complex it is. Therefore, there must be God who created the universe.”
- “I simply don’t understand how vaccines could be safe for children; therefore, I will not get my child vaccinated.”
- “I cannot imagine a life without divine purpose; therefore, I believe in god.”
- “I just can’t see how the big bang theory could be true.”
- “I don’t understand how the evolution theory could really explain life on earth, so I choose to believe in creationism.”