Examples for Applying Deduction in the Juridical Works of Sheikh Toosi

Deduction and the way of dealing with it are one of the oldest issues in the jurisprudence and principles of the religious schools. Meanwhile, general approach in Shiite school has been a negative one during the history and is still continue, but the important subject that we should pay more attention to it irrespective of ideas of jurisprudents is their dealing with the deduction in juridical books. It can be found in juridical books some cases that seem to be the cases of using deduction. This subject is incompatible with the famous view of Shiite, that is, nullity of deduction. The present article with this approach and depending on the books of Sheikh Toosi has investigated the cases that have been specified to their being deduction or the definition of the deduction conforms to it. Hasn’t the reality and the nature of the deduction in view of jurisprudents have a completely clear concept so that new definition can be given for the correct and incorrect deduction or the problem goes back to the practice there happened a kind of carelessness or even though they seem deduction apparently and at first glance, these cases are not invalid deduction in principle. It appears that to provide the definite answer to these questions, it is necessary for jurisprudents to study the question of deduction for the second time.