yastu manyate abhyāsavatyām api pravṛttau tādrūpyalakṣaṇaliṅgadarśanādanumānata evārthaprāpaṇaśaktilakṣaṇaprāmāṇyaniścaya iti sarvatra parataḥprāmāṇyāvasāyo na kvacid eva svata iti
Some hold that "Even in the case of repeated cognition, the certainty of validity - characterized by the capacity to lead to [knowledge of] the object - comes only from inference based on seeing the mark of similarity, so validity is always known through external means and never intrinsically."