 There are several reasons to think that deductive logic is not an adequate tool for dealing with this phenomenon. In order to apply deduction to the laws and the initial conditions, the laws must be represented in a form that admits of no exceptions. This would require explicitly stating each potentially relevant condition in the antecedent of each law-stating conditional. This is impractical, not only because it makes the statement of each and every law extremely cumbersome, but also because we know that there are many exceptional cases that we have not yet encountered and may not be able to imagine. Defeasible laws enable us to express what we really know to be the case, rather than forcing us to pretend that we can make an exhaustive list of all the possible exceptions.