I've mentioned personhood previously, and this is one of the posts that I'd urge everyone to read:
In 'I'm Still Here', (see previous post), John Zeisel poses a question that should really stop us in our tracks: 'Does a person have to speak intelligibly, to remember the names of recent prime ministers, or to be independent in caring for him or herself in order to be a person?'
There's only one answer to that.
But accepting the answer intellectually, as most people who aren't neurologists would, doesn't necessarily make it certain that you will always remember the answer and act accordingly. As I've indicated at various points in the blog, I read what some experts say about people with dementia and wonder if they spend much time reflecting on the nature of 'personhood'.