SHOULD WE ACCEPT THE PREMISES?

Perhaps Harold has a bad memory, has kept bad records, or is a poor ob- server. For some obscure reason, he may even be lying. It is important to ask this question explicitly, because fairly often the premises, when challenged, will not stand up to scrutiny.

If we decide that the premises are acceptable (that is, true and justified), then we can shift our attention to the relationship between the premises and the conclusion and ask how much support the premises give to the conclu- sion. One commonsense question is this: “How many times has Harold tried to use Canadian quarters in American payphones?” If the answer is “Once,” then our confidence in his argument should drop to almost nothing. So, for statistical generalizations, it is always appropriate to ask about the size of the sample.