Nyāya Sūtras 63.4

63.4

samānasya dharmasyādhyavasāyāt saṃśayo na dharmamātrāt/ atha vā samānam anayor dharmam upalabha iti dharmadharmigrahaṇe saṃśayābhāva iti/

Doubt arises from the apprehension of a common property, not from a mere property. Alternatively: when there is apprehension of both property and property-possessor, as in "I apprehend a property common to these two," there is an absence of doubt.