أَتَحْكُمُ عَلَى جَمِيعِ التُّجَّارِ بِغَيْرِ بَيِّنَةٍ؟
Would you judge every merchant without evidence?
In this setting, the question can function as rhetorical denial (inkār), challenging an unsupported generalization rather than requesting factual information. By contrast, “أَلَيْسَ الْحُكْمُ بِحَاجَةٍ إِلَى دَلِيلٍ؟” can seek the listener’s admission of an accepted principle, a taqrīr effect.
Both look interrogative, yet one rejects a claim while the other elicits agreement with a premise. Context and speaker intention decide which function is operative.