> Thoughts that 'bubble up' all the way to linguistic representation in the mind are definitely conscious, while it's also possible to make some sense out of brain activity that doesn't quite find words. For example, playing ping pong or some other sport would be exceedingly difficult if you had to use the linguistic part of your brain in order to make sense of what you're doing.

Conscious brain activity always struck me as the primary meaning of "thought". The idea of conflating "thought" with unconscious brain activity just seems to devalue the word itself rather than bring some utility or added understanding to the table.

Personally, I don't think of breathing as a thought at all, or my heart beating, even though it's evidently controlled by the brain, evidently also the source of thoughts. I only really ever have evidence of thoughts as distinct from other brain functions because I experience them consciously.