Um...the same physical body (yours, in this case) is taking in data through senses and is processing these data. One external, one internal, but only one you.Yes, but that doesn't explain why the sensation of "self" seems to be "mixed" if you will, with our experience of the sensations dervived from external world? How is it possible to mix them if there wasn't something very similar about them?
This isn't that difficult, Iacchus.