Vaisesika Sūtra 7.2.23

परत्वापरत्वयो परत्वापरत्वाभावोऽणुत्वमहत्त्वाभ्यां व्याख्यातः ॥२३॥

The absence of distinction between otherness and non-otherness is explained in terms of minuteness and greatness.