I think what Kazan is saying is that the Method isn't a thing. It's an action, a process, a skillful or effective way of achieving a specific artistic task. It's not a pair of shoes. It's discovering how to walk. I did an affective memory at the Actors Studio years ago, after which Lee Strasberg said, "Now that's an affective memory. Darling, tell them how you did it." When I explained my process, Strasberg replied, "That's not how you do an affective memory! But that's what the Method is all about. It's a way of work!" You find your own way of carrying out your own and your character's internal truth-within your body, mind, and soul.