Peirce (EP1:42, W2:227 fn4) remarked that ‘just as we say that a body is in motion, and not that motion is in a body[,] we ought to say that we are in thought and not that thoughts are in us.’ According to Yuri Lotman, we ought to say both:
The individual human intellect does not have a monopoly in the work of thinking. Semiotic systems, both separately and together as the integrated unity of the semiosphere, both synchronically and in all the depths of historical memory, carry out intellectual operations, preserve, rework and increase the store of information. Thought is within us, but we are within thought, just as language is something engendered by our minds and directly dependent on the mechanisms of the brain, and we are with[in] language. And unless we were immersed in language, our brain could not engender it (and vice versa: if our brain were not capable of generating language, we would not be immersed in it). The same with thought: it is both something engendered by the human brain and something surrounding us without which intellectual generation would be impossible. And finally the spatial image of the world is both within us and without us.
— Lotman (1990, 273)