Eckhart Tolle distinguishes using thinking as a tool from being used by it. When thinking assumes your identity, he says, you are possessed by your own mind.
Transcript
The mind-made sense of self is a terrible curse. [clears throat] And that is something that we need to transcend. So that we can actually use thinking in a powerful, focused, constructive way and actually create and manifest things through thinking. Thinking is a amazing tool. Where thinking becomes destructive is when it assumes your identity. Then when you do not think, but thinking happens to you. So in other words, I am actually possessed by my own mind.