…ve prosthetics surround us, plugging into our brain and extending its problem-solving capabilities. Your smartphone. Your laptop. Google search. The cognitive tools your were gifted in school. Books. Other people. Mathematical notation. Programing. The most fundamental of all cognitive prosthetics is of course language itself — essentially an operating system for cognition, without which we couldn’t think very far. These things are not merely knowledge to be fed to the brain and used by it, they are literally external cognitive processes, non-biological ways to run threads of thought and problem-solving algorithms — across time, space, and importantly, across individuality. These cognitive prosthetics, not our brains, are where most of our cognitive abilities reside.