I'd say meditators discover that "I am not my thoughts" instead. The next question would be "what is 'I'?" (it is one of the most profound questions ever) Generally speaking we don't "control" anything. Physically, we just interact with the environment, there's no "controller" nor "controllee" so to speak. In terms of soul-speak, we just experience the world, but our thoughts shape the world as well (which could feel like some form of control -- but really shouldn't be thought of as such).