The Rainbow
What are we to make of the rainbow?
Rainbows occur when reflection and refraction of direct sunlight takes place through water droplets in the air. So how could this have been a sign if rainbows had always been occurring naturally? Some commentators have suggested an answer which addresses a number of issues. They suggest that prior to the flood the planet had around it a canopy of cloud. This cloud would mean that all sunlight would arrive diffused, so no rainbows. This proposed canopy of cloud would also be the source of all the water that fell as rainfall in such copious, and never to be repeated, quantities. With the elimination of this original cloud canopy the first rainbow would be an assurance that such a flood neither could, nor would, ever happen again.
This potential answer to the rainbow question also addresses the longevity issue of these early patriarchs. How could men and women live for several hundreds of years? Old age is not all that easy to account for medically, since our bodies have natural self-repairing reactions to physical damage. But it is known that radiation from direct sunshine is a component of ageing. If there had only been diffused sunlight before the flood that might be an important factor in the longevity enjoyed by these ante-diluvian people.
So one by-product of the removal of the cloud canopy would be increased radiation, and with it a reduction of life expectancy. Which is what we read of in the closing sections of the Seth family history, in the event associated with the tower building at Babel.
With the tower building in Babel, which is usually identified as the later Babylon, we have (possibly) a mythological answer to the question: why are there so many different languages, some so dissimilar that they cannot easily be traced to a common origin? The answer given in the Seth family chronicle is that it was an act of Yahweh, to protect the people of that day from their own ambitious scheming. Ancient languages are interestingly very complex. If you look at the inflected written languages that are about as old as we have evidence for, Sanscrit, classical Greek, and Latin, the oldest is far more complex in terms of conjugations, declensions, tenses, and so on, than its younger companion Greek, which itself has more moods, tenses, and cases than the even younger Latin. Evolution of language tends towards simplification rather than increased complexity, which we see even in English, which drops options like the now archaic 'thee' and 'thou' and many similar current omissions from the language of the 15th and 16th century. So the fundamental question about the complexity and differentiation of language was a natural one to need answering.