Where does the mind end and the world begin? Is the mind locked inside its skull, sealed in with skin, or does it expand outward, merging with things and places and other minds that it thinks with? What if there are objects outside—a pen and paper, a phone—that serve the same function as parts of the brain, enabling it to calculate or remember? You might say that those are obviously not part of the mind, because they aren’t in the head, but that would be to beg the question. So are they or aren’t they?

Consider a woman named Inga, who wants to go to the Museum of Modern Art in New York City. She consults her memory, recalls that the museum is on Fifty-third Street, and off she goes. Now consider Otto, an Alzheimer’s patient. Otto carries a notebook with him everywhere, in which he writes down information that he thinks he’ll need. His memory is quite bad now, so he uses the notebook constantly, looking up facts or jotting down new ones. One day, he, too, decides to go to moma, and, knowing that his notebook contains the address, he looks it up.

Before Inga consulted her memory or Otto his notebook, neither one of them had the address “Fifty-third Street” consciously in mind; but both would have said, if asked, that they knew where the museum was—in the way that if you ask someone if she knows the time she will say yes, and then look at her watch. So what’s the difference? You might say that, whereas Inga always has access to her memory, Otto doesn’t always have access to his notebook. He doesn’t bring it into the shower, and can’t read it in the dark. But Inga doesn’t always have access to her memory, either—she doesn’t when she’s asleep, or drunk.

Andy Clark, a philosopher and cognitive scientist at the University of Edinburgh, believes that there is no important difference between Inga and Otto, memory and notebook. He believes that the mind extends into the world and is regularly entangled with a whole range of devices. But this isn’t really a factual claim; clearly, you can make a case either way. No, it’s more a way of thinking about what sort of creature a human is. Clark rejects the idea that a person is complete in himself, shut in against the outside, in no need of help.

https://www.newyorker.com/magazine/2018/04/02/the-mind-expanding-ideas-of-andy-clark

Andy Clark on the Extended Mind
Does your mind extend beyond your skull? Andy Clark, who developed the theory of the extended mind with David Chalmers thinks it does. He explains the idea here.

https://philosophybites.com/2017/03/andy-clark-on-the-extended-mind.html