A Comparative Study of the Conditions And Effects of “Exchange Liability” In ‎Iranian and Islamic Law, And “The Theory of Cause” In Civil Law

Problem; the liability for contractual consideration is one of the most important issues in synallagmatic contracts. The truth of “Exchange Liability” exists in all legal systems and it is discussed under a special title. Among these titles are "Theory of Cause" in the Civil Law system and "Exchange Liability" in Imamiyah jurisprudence. Exchange Liability and theory of Cause are both liabilities for contractual consideration, and they are rooted in agreement, but maybe, the conditions, jurisdiction and their effects are somewhat different in these two legal systems. The main issue in this research is what are the similarities and differences between “Exchange Liability” and "Theory of cause" in terms of conditions, scope, and effects?Aim; Therefore, the aim of this research is a comparative study of the conditions, jurisdiction, and effects of “Exchange Liability” and “The Theory of Cause.Method; This will be done in a descriptive and analytical method.Findings and conclusion; According to the findings of this research, despite the similarities between these two theories in the mentioned aspects, in terms of some works, including the amount of compensable damage, as well as the conditions and jurisdiction, significant differences between them are observed. For example, "Exchange Liability", unlike "theory of cause", is specific to synallagmatic contracts.