Sarvadarshanasangraha 12.89

12.89

tathā pramājñaptir api jñānajñāpakasāmagrīta eva jāyate/ na ca saṃśayānudayaprasaṅgo bādhaka iti yuktaṃ vaktum/ saty api pratibhāsapuṣkalakāraṇe pratibandhakadoṣādisamavadhānāt tadupapatteḥ/ kiṃ ca tāvakam anumānaṃ svataḥpramāṇaṃ na vā/ ādye 'naikāntikatā/ dvitīye tasyāpi parataḥprāmāṇyam evaṃ tasya tasyāpīty anavasthā duravasthā syāt/

(b.) We maintain that the recognition of right knowledge is produced by the same causes only which make us perceive the first knowledge[55] [sc. the eye, mind, &c.] Nor can you object that this view is precluded, because it would imply that there could be no such thing as doubt; for we answer that doubt arises in cases where, although all the causes which produce knowledge are present, there is also the simultaneous presence of some opposing cause, as a "defect," &c.

As for your argument [O Naiyāyika! given supra, in p. 198, lines 17-24], I ask, Is your own argument an authoritative proof by itself or not? If it is, it proves too much [for it would properly apply to itself and lead us to infer its own dependence on external proof, whereas you hold it to be independent of such]; and if it is not, we should have a case of regressus in infinitum, for it will want some other proof to confirm its authoritativeness, and this too in its turn will want some fresh proof, and so on for ever.