There are at least two possibilities, and no doubt many more besides.
The first one turns around the Cartesian dictum, "Cogito ergo sum", "I think therefore I am". René Descartes got off to a brilliant start and then promptly took a wrong turn, completely missing the point of his inadvertent discovery.
He turned right, taking the very 'doubt' that he took as evidence of his 'existence', making it the keystone of his entire intellectual edifice. Instead, he should have turned left and investigated it. So as to realise it's causal factors, thereby realising it's true nature, "... thus I am simply the result of that thought".
The second possibility considers the two Grail Legend questions. "What does it mean?" and, "Whom does it serve?" The first investigates the object of attention. The second investigates the subject himself, using the same principles, in the same way, to find the same answer.
One could also think of a teaching given to Carlos Castaneda, Don Juan's "second attention": though others might not agree.