俱舍論記 5.162

5.162

「若爾何故至亦可了知」者，說一切有部責彼經部。雖無現比證知，而有聖教。經中既說有為之起等第六轉聲，復言了知，明知有體。

Regarding "If so, why ... can also be known?": the Sarvāstivāda rebukes that Sautrāntika. Although perception and inference do not establish knowing them, there is holy scripture. Since the scripture speaks of the arising of the conditioned, using the sixth grammatical case (genitive), and further says "can be known," it is clearly known that they have an entity.