‌Context & Objective: Because void contracts (ʿoqūd-e fāsed, legally defective agreements lacking valid effect) cannot establish contractual obligations, analyzing the nature of non-contractual liability (żamān-e qahrī, involuntary liability imposed by operation of law) and its relationship with the parties' constitutive intent (erādeh-ye enšāʾī, the intention to create legal effects) remains a central challenge in Imami jurisprudence (Fiqh). Three competing approaches address this issue: the first analyzes liability through mutual consent and the contractually stipulated price (mosammā, the agreed consideration) as a natural extension of contract formation; the second treats intent as entirely ineffective upon contractual collapse, basing liability exclusively on actual property value—whether fungible replacement (mesl) or market price (qeymat)—under general rules such as liability of possession (qāʿedeh-ye yad, liability arising from dominion over another's property) and destruction (etlāf, direct causation of loss); and the third views intent not as a cause of obligation, but as a measure that limits liability and negates gratuitousness (majjānīyat, transferring property without consideration). Examining this evolution alongside Articles 301, 303, 328, 365, and 366 of the Iranian Civil Code clarifies the boundary between pure non-contractual liability and liability arising from void contracts, asking whether voluntary entry into a bilateral exchange—regardless of knowledge or ignorance of invalidity—independently generates liability under the assumption of risk doctrine (qāʿedeh-ye eqdām, the rule that voluntary transactional undertaking entails accepting liability), or merely removes gratuitousness to activate general liability rules.
 ‌Method & Approach: Applying a doctrinal method and a critical analysis of the opinions of Twelver Shiʿi jurists, this inquiry traces the evolution of the assumption of risk doctrine from its position as a generative cause (ʿellat-e moḥdeseh, an originating cause that creates a legal obligation) in early jurisprudence and the Oṣūlī school (the rationalist-methodological school of Shiʿi legal theory) to an interpretive instrument in contemporary jurisprudence.
 ‌Findings: The prominent doctrine of independent causation (the view that transactional undertaking independently creates liability)—whether framed as an implied undertaking in early jurisprudence, as voluntary causation through customary inclusion in the Oṣūlī school, or as foreclosing recourse to the principle of no harm (lā żarar, the rule prohibiting uncompensated loss) and imparting a non-gratuitous identity to physical delivery—lacks argumentative efficacy due to three fundamental obstacles. First, ontologically and epistemologically, constitutive intent is particularized and cannot attach to general coercive legal rulings, separating genus from differentia in mental constructs is fallacious because the stipulated price is an indivisible entity, and intent cannot attach to gradually occurring usufructs. Second, legally, the primacy of liability of possession and the exclusivity of recognized grounds of liability show that the broad maxim holding anyone who undertakes a transaction liable lacks valid textual authority, while liability for usufructs stems from subordinate dominion over the underlying property. Third, mathematically, a quantitative mismatch exists between the stipulated price and actual market value, whether actual value exceeds the contract price or falls below the sum on which the owner conditioned consent. Conversely, contemporary functionalist approaches shift the doctrine from the substantive stage of establishing liability to the stage of proving and quantifying obligations, redefining its function through removing the obstacle of gratuitousness based on the inherent protection of property (eḥterām-e māl), limiting liability ceilings, and enforcing customary market practice.
 ‌Conclusion: Explaining the assumption of risk doctrine in void contracts requires the theory of contingent limiting disclosure (synthesizing the removal of gratuitousness with a ceiling on damages). Substantively, the parties' undertaking is not the generative cause of obligation; rather, inherent property protection and liability of possession establish liability once party intent negates gratuitousness. In quantifying damages, because an owner who knowingly consents to a stipulated price below actual market value waives protection over the excess, compensation is governed by the lesser of the two amounts (the lower of the stipulated price and actual value). Under Articles 301, 303, 328, 365, and 366 of the Iranian Civil Code, this standard preserves property protection while preventing unforeseen excess liability for authorized possessors in void contracts.