Created a throwaway for this, but is this not what people do?
Not so much imagining a conversation in your head, but playing through a conversation with "the other side" of the coin (be it an idea, plan, problem, solution etc) which are both yourself if that makes sense.
Is this not what the inner monologue to yourself is? Your inner is conversing with your outer monologue. Hard to explain.
Would consider myself to be both physically and mentally stable, no conditions etc.