Shankaracharya said to them, when you say with a sword, strike up a tree, strike somebody's head or strike a piece of cloth, what do you mean? Nothing. What form does Brahma have? Nothing. So, that, and it cannot be an object of perception, of thought, of language. Now using the thought, there is no language which will work like that and will work at this point. Using the thought pointing back towards that, you realize I am that, but that I am that ness is revealed by that consciousness only, not by the Vriti. And that is his explanation.