76. The disciple said, Knowledge is the meaning of a root and therefore surely consists of a change; and the Knower (as you say) is of a changeless nature. This is a contradiction.(from Upadesa Sahasri Chap.II:The Knowledge of the Changeless)
77. Teacher: It is not so. For the word knowledge is used only in a secondary sense to mean a change called an action, the meaning of a root. A modification of the intellect called an action ends in a result in itself which is the reflection of Knowledge, the Self. It is for this reason that this modification is called knowledge in a secondary sense, just as the action of cutting a thing in two is secondarily called its separation in two which is the ultimate result of the action of cutting the thing.
The idea here, as I understand it, is that you have various inflections of the root ‘know’ e.g. knowing, known, knowable, knowledge. By implication you have also the polar opposite of ‘not know’ or ‘ignorance’ and its cognates. So we seem to have a condition i.e. knowledge, that arises out of activity or is an activity and is therefore not changeless. The Teacher does not deny that there is activity but he holds that it is only by being pervaded by Consciousness that knowledge arises out of it. Without that there would be no body of knowledge. This is the ‘secondary sense’ or ‘reflection’ of knowledge. In the cinema screen analogy, it’s as though the action had to pass through the permanent screen in order to be known.