yathoktaṃ śābare bhāṣye naivañjātīyakeṣvartheṣu puruṣavacanaṃ prāmāṇyamupaiti, andhānām iva vacanaṃ rūpaviśeṣeṣviti /
As it is stated in Śabara's Bhāṣya: "In matters of this kind, human testimony does not attain validity, just as the words of blind [people] [do not attain validity] regarding specific colors."