Sarvadarshanasangraha 10.44

10.44

[The answer is:] It is merely an illusion, like [the cognition] “The sky is blue”; enough with the burden of old arguments! For this very reason, darkness does not have an superimposed color, since superimposition is impossible without cognition of a substratum, and because the eye, lacking the auxiliary aid of external light, is not observed to have the capacity to superimpose color. Nor is this cognition non-ocular, since its conformity [to the functioning of the eye] is uniquely established. For this very reason, it is not an absence of the cognition of light, because, according to the rule that an absence is grasped by the same sense organ that grasps its counterpositive, this would entail that it is mental. Therefore, darkness is simply the absence of light.