When do we say that something contradicts reason?

Rational judgment is the mind's knowledge of a relationship, whether affirmative or negative. Theologians (Mutakallimun) in matters of Islamic law have claimed that Islamic law contradicts reason, but this is incorrect. Islamic law does not contradict reason, because the Revealer of the Law and the Creator of reason is Allah. If there is what appears to be a contradiction between transmitted texts (naql) and reason (aql), then either the transmitted text is not authentic, or the indication of reason for its impossibility is not established. The contradictions and disagreements among the theologians indicate that their rational arguments do not constitute a valid proof. Sheikh al-Islam Ibn Taymiyyah clarified this in his book "Darʾ Taʿāruḍ al-ʿAql wa al-Naql" (Averting the Conflict between Reason and Transmitted Texts).