I am a very different person than I was 10 years ago - I think so, and people around me think so. But the question of "who I am, on the inside," I think I would answer with traces of that old self, even though that old self never outwardly manifests anymore.
So there's "me, me," the version that is quick to judge others, has a hyper-inflated ego, wants to sit around and watch netflix, and eat a lot of donuts. Then there's "I wish I was this guy, me," the 15% bodyfat 225lb bench 10x programmer that everybody loves, and then there's the "me that other people see," which is somewhere between the other two versions. So which one is "me?" Me-me has a desire to become "I-wish-me" and is acting on that desire in concrete ways, and tamps down "me-me" mindsets in order to achieve that. So are there two individuals in this body fighting? What's going on?
Looking forward to reading more about Shaiva Tantra, thanks for bringing it up.