Argument from false premises facts for kids

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An argument from false premises is a line of reasoning which can lead to wrong results. A false premise is an untrue proposition that forms part of the basis of a logical syllogism. Since the premise (assumption) is not correct, the conclusion drawn may also be wrong. However, whether or not an argument is "valid" depends on whether it is consistent, not whether its premises are true.

For example, consider this syllogism:

• 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 not always true, because the first premise can be false – someone could have hosed down the streets, a street cleaner could have passed, the local river could have flooded, and so on. A simple logical analysis will not reveal the error in this argument, since that analysis assumes that all the argument's premises are true. For this reason, an argument based on false premises can be much more difficult to 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 of course does nothing to prove the first premise, but can make its claims more difficult to refute.

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