View source for False premise

{{distinguish|false pretenses}}
{{short description|Incorrect proposition that forms the basis of an argument}}
{{more sources|date=February 2024}}

A '''false premise''' is an incorrect [[proposition]] that forms the basis of an argument or [[syllogism]].  Since the [[premise]] (proposition, or assumption) is not correct, the conclusion drawn may be in error. However, the [[Validity (logic)|logical validity]] of an argument is a function of its internal consistency, not the [[truth value]] of its premises.

For example, consider this syllogism, which involves a false premise:

* If the streets are wet, it has rained recently. (premise) 
* The streets are wet. (premise) 
* Therefore it has rained recently. (conclusion)

This argument is logically valid, but quite demonstrably wrong, because its first premise is false — a [[street cleaner]] may have passed, the local river could have flooded, etc.  A simple [[deductive system|logical analysis]] will not reveal the error in this argument, since that analysis must accept the truth of the argument's premises.  For this reason, an argument based on false premises can be much more difficult to [[falsifiability|refute]], or even discuss, than one featuring a normal logical error, as the truth of its premises must be established to the satisfaction of all parties.

Another feature of an argument based on false premises that can bedevil critics, is that its conclusion can in fact be true.  Consider the above example again.  It may well be that it has recently rained and that the streets are wet.  This does nothing to prove the first premise, but can make its claims more difficult to refute.  This underlies the basic [[epistemology|epistemological]] problem of establishing [[causal relationships]].

[[Large language models]] often fail to appropriately answer questions based on false premises, but can be trained to respond correctly.<ref>{{cite journal |last1=Hu |first1=Shengding |last2=Luo |first2=Yifan |last3=Wang |first3=Huadong |last4=Cheng |first4=Xingyi |last5=Liu |first5=Zhiyuan |last6=Sun |first6=Maosong |title=Won't Get Fooled Again: Answering Questions with False Premises |journal=ArXiv |date=2023 |arxiv=2307.02394 |url=https://arxiv.org/abs/2307.02394 |access-date=4 February 2024}}</ref>

== References ==
{{reflist}}

==See also==
*[[Premise]]
*[[Co-premise]]
*[[Inference objection]]

{{DEFAULTSORT:False Premise}}
[[Category:Deception]]
[[Category:Syllogistic fallacies]]

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