Acceptance of propositions without sufficient evidenceBased on the critique of the concept of validity by William James and Allameh Tabatabai

“VALIDITY” is a commonly used term in epistemology. James makes use of constructional as a solution for strong rationalism and considers that as “assumption of belief” or “perceiving acceptance”. The criticisms to the theory of Will to Believe convey that a constructional issue corresponds to a reality in development or substantiation and also the truth is reduced to usefulness. Constructional in Allāma Tabātabā’ī’s theory of constructional perceptions is interpreted as artificiality and constructing some concepts to fulfill a human’s basic needs. Although this theory does not claim the truth for constructional perceptions, it conveys that the practical and ethical concepts and rules are artificial and relative reproductions. By offering a new explanation of constructional, without any alteration in the artificial or genuine perception of ethical issues, the present study aims to prepare a solution for the epistemological problem of some necessary and useful beliefs for which there is not sufficient evidence. In this analysis, by considering constructional as “assumption of belief” or “perceiving acceptance”, without any reliance on the truth that is expected from the consequences of a belief, it is showed that the constructional perceptions can be acknowledged as valid in the field of theoretical and practical sciences.