Abstract

Hempel's theory of evidence seized from the problems arising - the so-called paradox of validated - we look back and review the logic of conditional statements and found that the relationship between symbolic logic truth table wrapped in conditions such as we have elements that are not as matter of course. As the conditional statement is in fact a logical statement, all statements in the most relevant and practical, so in the face of the check as evidence of a reasonable construction of the theory of a class of practical problems, the more full use of logic, the closer to an absurd result - which , Hempel's theory of prosecution evidence is providing us the most typical example. Conditional statement problem in binary logic system can not be resolved, so we must resort to a further three-valued logic system, in order to get a reasonable truth conditional statements, and to solve such as "paradox of validated," the contradictions of a class