Quote Originally Posted by FUBeAR View Post
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 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 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 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.
Your syllogism is all wet!