Seyyed Kamal Haydari's theory of "permissibility of adherence to all divine and human religions" seeks to legitimize religious pluralism within Islam, drawing on contemporary Western epistemology and Quranic evidence. However, due to its clear conflict with Islamic scriptural texts and epistemological foundations, this theory offers a revisionist interpretation of modern theological issues that demands serious scrutiny.

This study aims to analyze and critique the Quranic evidence supporting this theory, evaluating whether the cited verses actually substantiate the claim that all religions are equally valid for adherence.

Eight verses cited by Haydari—gathered from his written works and oral sessions (personal website and teaching meetings)—were examined using qualitative content analysis and interpretive methods. Each verse was critically assessed at two levels—"understanding the verse" and "relevance to the claim"—by referring to authoritative Sunni and Shia commentaries and principles of exegesis.

The findings reveal that the eight cited verses, due to fragmented interpretation divorced from context, neglect of the occasions of revelation, and confusion between the levels of proof and ontological reality, do not support the theory's claim. Furthermore, the epistemological basis of this theory—namely, the impossibility of ascertaining objective truth—stands in direct contradiction to the Quran's guiding purpose and the possibility of knowing truth within Islam's epistemological framework.