One of the important issues in the philosophy of social sciences is to explain the relationship between the explanation and interpretation in understanding social phenomena; this is generally explained by the distinction between cause and reason. A social explanation is explaining why that event occurs based on the causes of the occurrence, but in interpretation, the goal is a deep understanding of a social action based on the reasons and intent of the actor. In this paper, based on a description of the distinction between natural cause and divine cause, it is shown that all phenomena in the natural world are underdetermined; as a result, the “laws of nature”, which express the natural relations of objects, are the only subsidiary factor for the realization of natural and social events. In the field of social phenomena, the “free will” is the immediate cause of the determination of social phenomena, but due to the possibility of violating the free will from enthusiasm and its motivating reasons, the reasons are the only subsidiary factor for social actions.