The Compendium of Caraka 3.8.36

3.8.36

athottaram---uttaraṃ nāma sādharmyopadiṣṭe hetau vaidharmyavacanaṃ, vaidharmyopdiṣṭe vā hetau sādharmyavacanam/

Now, the counter-argument: a counter-argument is the statement of dissimilarity when a reason has been stated through similarity, or the statement of similarity when a reason has been stated through dissimilarity.