Bhṛgu–Bharadvāja-saṃvāda: Vānaprastha-parivrājaka-ācāra, Abhaya-dharma, and Lokānāṃ Vibhāga (Śānti-parva 185)
वाय्वग्न्यशनिनिर्घोषै: फल पुष्पं विशीर्यते । श्रोत्रेण गृहते शब्दस्तस्माच्छुण्वन्ति पादपा:
vāyv-agny-aśani-nirghoṣaiḥ phala-puṣpaṃ viśīryate | śrotreṇa gṛhyate śabdas tasmāc chṛṇvanti pādapāḥ ||
婆罗陀婆阇说道:“风、火与霹雳的轰鸣之声,使树木的果与花震落而坠。声音由听觉之官所摄取;因此可确立:树木亦能听闻。”
भरद्वाज उवाच
The verse argues from observable effect (trees shedding fruits/flowers when exposed to loud natural sounds) to a philosophical conclusion: since sound is known through the faculty of hearing, trees must possess some capacity to apprehend sound—an assertion of non-human sensory capability.
Bharadvāja presents a reasoning example within a didactic discussion: he cites the reaction of trees to the loud roar of wind, fire, and thunder as evidence supporting the claim that trees can ‘hear’ (i.e., respond to sound through an appropriate faculty).