Characteristic Deduction, Induction and Fallacy Arguments can be divided into three categories on the basis of their logical strength.
Some explanatory remarks are in order.
First, the probability concept used in these definitions is that of conditional probability, the probability of the conclusion given the premises. In talking about this probability we are not assuming that the premises are true, we are commenting on what bearing it would have on the conclusion's status if the premises were known to be true. Thus we can calmly assert that the probability that the Earth is about to be destroyed, given that it is about to be destroyed by conversion to an amorphous plasma by phaser fire from Vogon destructor ships, is 1. This means only that it is impossible that the Earth should be destroyed in that particular way without being destroyed. This simply means that if I were to win such a sweepstakes this year, I would almost certainly be debt free next year.