yata ete viśeṣapratyayāḥ, naca viśeṣapratyayā ākasmikā yuktāḥ naca, paramparaṃ mūrtadravyavyapekṣā, itaretarāśrayatvenobhayābhāvaprasaṅgāt, tasmād anyanimittāsambhavād diśa etāni liṅgāni
Since these are specific notions, and specific notions cannot arise randomly, nor can they depend mutually on corporeal substances (as that would lead to mutual dependence and thus the non-existence of both), therefore, due to the impossibility of any other cause, these are the marks of Space.