Guys, this is a very basic question I am having. It is not necessarily specific to this lesson. But related to almost every lesson, i guess.
My question is : Do we have a proof that every part of our physical body changes over the years? I am asking this in reference to the idea that only "I" is changeless and permanent, and always already present. Everything else changes. But, how do we know if everything else (specifically everything about our physical body) does really change or not? How are we sure that the sense of "I" that we find to be always already present, doesn't come from some physical parts of our body that do not change for a lifetime? May be something like brain cells, that are known to last almost a lifetime or more..
Thanks sooo much in advance!