Van Deurzen, an existential psychotherapist, identifies self-reflection and self-discovery as the core components of existential therapy through her examination of its various aspects. She posits that humans, distinct from other creatures, possess a fluid and dynamic identity. This, according to her, allows individuals to determine their own existence and identity. Mulla Sadra, on the other hand, acknowledging the fluidity and dynamism of human identity, proposes that human existence extends beyond this world, encompassing multiple worlds and levels of existence, and within each world, individuals find a corresponding level of existence, so that through their own free will, humans determine their position in this system of existence. By elevating their existence to the level of rational existence, they can transform themselves into a rational world akin to the objective world. This paper aims to demonstrate, based on the views of these two thinkers on human beings’ fluid and dynamic existence, the self-determining nature of the human self, the place of self-discovery in existential therapy, and Sadra's perspective on self-discovery, that Sadra’s view can potentially serve as the foundation for an existential therapy within Iranian-Islamic culture.