Vaisesika Sūtra 5.2.02

तद्विशेषेणादृष्टकारितम् ॥२॥

tadviśeṣeṇādṛṣṭakāritam ॥2॥

[तत्-विशेषेण (tat-viśeṣeṇa) - by its particularity; अदृष्ट-कारितम् (adṛṣṭa-kāritam) - caused by unseen force;]

It is particularly caused by the unseen-force.