Mental existence and knowledge (ʿilm) are compiled in two separate chapters in the standard textbooks of the seminary curriculum. Their distinct classification suggests a differentiation between them; yet, their common participation in cognition and awareness suggests similarity between them. This simultaneous distinction and similarity has hindered a profound understanding of these two important philosophical issues. Moreover, few philosophers have undertaken an independent and detailed comparative analysis of mental existence and knowledge. On the other hand, the dominant view concerning mental existence and knowledge considers them to be a single reality with two different aspects or considerations. In contrast to this prevailing position, Ayatollah Javadi Amoli maintains that mental existence and knowledge are two distinct realities. This perspective has received comparatively little scholarly attention despite containing subtle and valuable insights. Accordingly, the present study examines Ayatollah Javadi Amoli’s view and expounds his original theory with four substantiated arguments. It then demonstrates the impact of this theory upon three philosophical problems. The final conclusion established by this research is the ontological distinctness between knowledge and mental existence.