A Reflection on the Authority of Prospective Istishab

The common and conventional meaning of Istishab is that the definite affair should be of the past and the doubted affair should be of the present time; however, sometimes in the field of inference, we are encountered with a phenomenon, known as prospective Istishab in which the definite affair exists at the present time and the doubted one relates to the future. The famous opinion among the later Usulis is that such Istishab is applicable and the absoluteness of the texts related to Istishab is the main argument of the famous Usulis for this claim. The present article, through analyzing and studying the arguments of the proponents and opponents of the application of this Istishab, while refusing the famous opinion and accepting the non-authority viewpoint, accepts the existence of behaviors from the divine lawgiver and the people of the religion which are thought to be identical to the content of this Istishab based on a kind of certainty as to the subsistence of the state or a rational ruling on the necessity of starting the act when this is not problematic or on the basis of the “unity of the state of the phenomenon at a later time with its first state” rule without its relationship with prospective Istishab.