समवायाभ्युपगमाच्च साम्याद् अनवस्थितेः ॥ १३ ॥
samavāyābhyupagamācca sāmyād anavasthiteḥ || 13 ||
samavāya-abhyupagamat—Samavaya being admitted; ca—also; sāmyāt—equality of reasoning; anavasthiteḥ—‘regressus in infinitum’ would result.
13. (the Vaiseshika theory is untenable) also (because if involves) a regressus in infinitum on similar reasoning, since it accepts Samavaya.
Samavaya or inseparable inherence is one of the seven categories of the Vaiseshikas. They say it is this that connects the dyad with its constituents, the two atoms, since the dyad and the atoms are of different qualities. In that case Samavaya (inherence) itself also being different from these dyads and atoms, which it connects, another Samavaya will be required to connect it with these, and that in its turn will require another Samavaya to connect it with the first Samavaya and so on without an end. Hence the argument would be defective, and consequently the atomic doctrine, which admits Samavaya for combination, is inadmissible.