وأما القول بموجب العلة: فهو تسليم كون الوصف علة، وبيان أن معلوله غير ما ادعاه المعلل
This objection accepts the attribute as a cause but argues that its effect differs from the effect alleged by the proponent.
The opponent does not dispute the existence or causal relevance of the attribute. Instead, the response is: the cause may be real, but it establishes a different legal consequence. The issue is thus the exact object of the ruling rather than the existence of the cause.
A contractual condition might relate to the contract's formation, designation of the price, or immediate exchange of possession; these are distinct effects.