Neither. One of the things you do on the path is to look into things like that, and search and see if there is a locus of control or anything that could count as a permanently existing self continuing from one moment to the next. And when you look closely you find that there isn't one, internal or external, at least that is what the Buddha found when he became enlightened.
But we each have to search for ourselves. It's not something you can learn as a philosophy. But have to find out for yourself directly. u
So that's the path, and the teaching on non self basically, I'd say. If you have an open mind about this, even if sceptical about it, that is fine, but interested to follow it up and find out more, then that's the path of the Buddha.
But as you follow the path, you may encounter various inspirations that, because they are outside of the ordinary familiar self as we are used to thinking of it, seem like they come from outside. Really are neither inside or outside.
For instance impulses of unselfish compassion, generosity or loving kindness. In their purest form then tend to relate to them as like an inspiration that came from outside almost "I've no idea why I did that" "Was just in the impulse of the moment" etc.
The Buddha said that you can eventually see through the illusion of a self, that he did that himself. Not as something to eradicate because it was never there in the first place. Just wake up from an illusion you've been caught up in since forever. So then that spontaneous inspiration we may just glimpse in moments is what we at some moment suddenly find out we are and always were. And everyone else also.