Muslim philosophers have offered different interpretations and possibilities on kinesis in category (substance and accident). Two interpretations are most important among others. According to one interpretation, which in this article is referred to as Avicenan approach, kinesis is a mode of corporeality and should not be understood as a fluidity of substance or accident. On this view, kinesis in substance, which implies nothing less than the fluidity of substance, would be impossible. Upon another interpretation, which is referred to as Sadrayian approach in this article, kinesis denotes a kind of being, both in substance and accident, and divides the being into fixed and fluid. According to the first approach, Avicenan approach, this kind of kinesis, from one point of view, falls short of the criterion of identity, so it is self-contradictory, and from another perspective, it compromises between "identity" and "otherness" in a contradictory manner.  The second interpretation, investigating the existential reality of kinesis, makes it clear that kinesis in substance and accident can be considered as fluid and unresting, implying a mode of being. This way the criterion of "identity" and "otherness" is derived from this mode of existence, not resulting in any contradiction.