2. The Polynesians were great navigators, they knew their stars. Observing how a star descends in the west to rise later again in the east, as if reborn, should have lead to ideas of a star in the east being young and a star on its way down in the west as being like an old man on his way to 'death'.

At first such words ('reborn', 'young', 'old', 'death' etc) would only have been easy words to use for expressing observed facts. Later the words would tend to take on a life of their own, 'infecting' especially the minds of those who knew little or nothing of navigation and stars.

Next newborn babies (especially of kings) would tend to be regarded as the old ones coming back, like the admirable stars which were rising again 'from the dead' in the east. The old generation would live on in the new generation:

"... And then she looked in her hand, she inspected it right away, but the bone's saliva wasn't in her hand. It is just a sign I have given you, my saliva, my spittle. This, my head, has nothing on it - just bone, nothing of meat. It's just the same with the head of a great lord: it's just the flesh that makes his face look good. And when he dies, people get frightened by his bones. After that, his son is like his saliva, his spittle, in his being, whether it be the son of a lord or the son of a craftsman, an orator. The father does not disappear, but goes on being fulfilled. Neither dimmed nor destroyed is the face of a lord, a warrior, craftsman, an orator ..." (Popol Vuh)

The two faces in ariga erua are reflections of each other. A star which is rising in the east is the same as the one who went down in the west. Therefore it should be one body with two heads (one in the evening sky and one in the morning sky).