US-P18.073ab ।US-P18.073cd ॥
In plain words
If that is how it stands — if they are seen by nothing other than themselves — then say what rules out another seer. Suppose, then, that their being there and their being gone are never grasped by anything else.
Close to the Sanskrit
If it is so that they are not seen by another, say what rules out that other seeing. Suppose, then, that their presence and absence are never apprehended by another.