I agree with this, although I think it's more precise to say a thought is correct insofar as it conforms to reality.
> Correctness of a thought is not a physical label. It's not a state. It's something you evaluate, something you compute with respect to knowledge you observe.
This appears to be illogical. The correctness of my thought (that is to say, whether it conforms to reality) is one thing; my evaluation of its correctness is entirely different. Further, correctness must be a 'state', or property, of a thought: otherwise you undermine your own argument (see below).
> nature does not put XML tags with correctness score on neurons.
I agree with this. But this supports my argument. An arrangement of neurons (or anything physical) cannot be correct or incorrect. But a thought can be correct or incorrect (you must think that, because you must think you're right and I'm wrong about this disagreement). Therefore a thought cannot be reduced to an arrangement of neurons (or anything physical).
> If one thought is right (about reality) and another thought is wrong (not about reality), then there must be aspects of thought that are distinct from the physical state of the brain.
Of course there is. Computation. Observation. A correctness of a thought isn't a function of thought itself, it's a function of thought and reality. Correctness of a thought is not a physical label. It's not a state. It's something you evaluate, something you compute with respect to knowledge you observe.
The way I see it, you're confusing a thought with computed properties of it. There is no privileged notion of correctness and nature does not put XML tags with correctness score on neurons.