[projektir]

> Are you saying that it's impossible to control your thoughts?

Given that thought generation is not a process that you (the person) actively control, that seems rather obvious. "Thoughts" would refer to all of them, and many thoughts are intrusive or otherwise do not originate from "you" (i.e., insights, creativity related thoughts, odd memories, associations, etc., etc.).

You can have thoughts about thoughts, and you have a greater control over those because you /are/ more or less actively generating those, but that's not true for most thoughts you have.

Even then, the control space is very limited (not truly deserving of the term control) and only available to people who practice a lot of introspection. CBT is a tool in making one's way there. It's not something that the average person can get up and do. "You can control your thoughts" is therefore not the most useful statement, we're not discussing what's possible in theory, we're trying to help a specific person.