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An argument consists of a set of sentences consisting of one or more premises, which contain the evidence and a conclusion, which is supposed to follow from premises. Bad arguments vs. good arguments: if the premises imply the conclusion, then the argument in question is a good one. If money grows on trees, then bill clinton is the prime minister of canada. Thus bill clinton is the pm of canada (conclusion) An argument is valid so long as the argument is such that the conclusion must be true if the premises are true. If it is raining then there are clouds in the sky. If i won the lottery (p), then i bought a lottery ticket(q) An invalid argument, by contrast is one in which it is possible for the premises all to be true but the conclusion false. Arguments with false premises may be valid and argument with true conclusions may be invalid.