قُلْ ءَآلذَّكَرَيْنِ حَرَّمَ أَمِ ٱلْأُنثَيَيْنِ أَمَّا ٱشْتَمَلَتْ عَلَيْهِ أَرْحَامُ ٱلْأُنثَيَيْنِ نَبِّـُٔونِى بِعِلْمٍ إِن كُنتُمْ صَٰدِقِينَ
"Say: 'Is it the two males He has forbidden, or the two females? Or what the wombs of the two females contain? Inform me with knowledge, if you are truthful.'"
I record this as my own reading: the method forces the other side into the detail of its own claim. If a prohibition has been laid down, it must be possible to say what has been forbidden. And when the detail is gone into, it becomes visible that the claim has no support.
And this demand is one link in the line of proof treated in many places in the index: al-Aḥqāf 46/4 (iʾtūnī bi-kitābin … aw athāratin min ʿilm), Luqmān 31/11 (fa-arūnī mādhā khalaqa), Ghāfir (al-Muʾmin) 40/35 (bi-ghayri sulṭānin atāhum), al-Qaṣaṣ 28/75 (hātū burhānakum). What al-Anʿām adds: the demand being put about a claim of prohibition.