anyatheti yadyavedatvamasya na jñāpyate tadā yattvayā śrutau vede anuktatvaṃ tasya sarvajñasyoktaṃ tat sandigdhāsiddhaṃ bhavet //
"Otherwise" means: if you do not establish its non-Vedic nature, then what you have stated about the omniscient one's non-mention in śruti would become doubtful and thus inadmissible [as a reason].