Dogen's "Rules for Meditation:"
"...neither trying to think nor trying not to think, just sitting with no deliberate thought..."
We attend to the present moment but do not concentrate on it. If we concentrated, then we would be trying not to think. When we notice that a thought has arisen and return our attention to the present moment, then we are preventing not thought but deliberate thought.
The arising of thoughts is neither an interruption to meditation nor a distraction from it but part of it. We see the thoughts, therefore do not allow them to operate unobserved.