Julie Adler

Purity or impurity (suddhi or asuddhi) is not the essential quality or nature of any object, because In that case the purification of a thing of which the scriptures talk would be impossible as the essential nature can not change, but if it changes it is not essential. Purity or impurity have therefore to be admitted to be the ideas of a particular subject which are firmly associated with a thing. It is why what is pure to one person is not so to another. For the idea of purity of one thing and impurity of another is inspired by the scripture in which an individual has faith.

…whatever is recognized to be one with samvit [energy (of) knowledge, consciousness] is pure and what is not so recognised is impure. Hence to those who look upon the whole universe as identical with self, the distinction between pure and impure does not exist.

Abhinavagupta