An interesting take on the idea of mind, that a substantial portion of it lies outside of our brain.
Link: Wikipedia on the Extended Mind Hypothesis
I regard this less as a Hypothesis than a way of reframing our ideas of mind - mind is shaped not only by our environment, is more than the sum of our own memories (think film and books), is in fact extended everywhere we can see and a great many places we cannot.
We can store our thoughts on paper, in computers, share them around the world, words, videos, can provoke responses, themselves extending our minds, our physical place - house, apartment, furnishings, knick-knacks, all contribute to the quality of mind, all are governed, managed, we can set up our computers, AI bot agents, to furnish us with news we want (or need), we can disregard the evidence of our senses and education in favour of what our phones tell us, our memories...
And - these media allow us to extend our mind both forward and backwards through time, we can remember fondly their acquisition just as others may remember us in the inheritance of said objects, the theory implies the existence of the person beyond their mortal lives...