The roots of the problem of the union of the intellect and intelligible can be found in the philosophies of Plato and Aristotle. It has indeed been more clearly explained in Plotinus' philosophy and the Neo-Platonic School and its followers. This problem has also been tackled by the thinkers of the Islamic world and had some advocates and opponents there. However, we can claim that it reached its culmination in the Transcendent Philosophy.
The present paper has examined the process of the evolution of this theory and its explanation in Mulla Sadra's philosophy following an analytic-critical approach.