Bakandha-nyaya: the logic of the duck and the bull's testicle

Expressions researched:
"Bakando nyaya" |"Logic of duck and testicle" |"bakanda-nyaya" |"bakandha-nyaya" |"bull is going and the testicle is hanging, and the duck is after it" |"bull is going on and testicle hanging, and another duck is going after him" |"bull, he has a testicle hanging, and the baka is thinking it is a fish" |"duck is such a fool that it runs after the testicles of a bull" |"testicle of the bull and the duck"

SB Canto 10.1 to 10.13

Illustrating the logic called bakāndha-nyāya, the duck is such a fool that it runs after the testicles of a bull, thinking them to be a hanging fish that can be taken when it drops. Thus the duck is always in darkness.

SB 10.3.20, Purport:

In this verse, the three colors mentioned-śukla, rakta and kṛṣṇa—are not to be understood literally, in terms of what we experience with our senses, but rather as representatives of sattva-guṇa, rajo-guṇa and tamo-guṇa. After all, sometimes we see that a duck is white, although it is in tamo-guṇa, the mode of ignorance. Illustrating the logic called bakāndha-nyāya, the duck is such a fool that it runs after the testicles of a bull, thinking them to be a hanging fish that can be taken when it drops. Thus the duck is always in darkness. Vyāsadeva, however, the compiler of the Vedic literature, is blackish, but this does not mean that he is in tamo-guṇa; rather, he is in the highest position of sattva-guṇa, beyond the material modes of nature. Sometimes these colors (śukla-raktas tathā pītaḥ) are used to designate the brāhmaṇas, kṣatriyas, vaiśyas and śūdras. Lord Kṣīrodakaśāyī Viṣṇu is celebrated as possessing a blackish color, Lord Śiva is whitish, and Lord Brahmā is reddish, but according to Śrīla Sanātana Gosvāmī in the Vaiṣṇava-toṣaṇī-ṭīkā, this exhibition of colors is not what is referred to here.