Daniel, thanks for that, and that whole post. It helps me see better what you’re focused on. Different people in this thread have argued that (1) Genesis records a decline in the human lifespan (2) that fits a decay curve (3) caused by the flood. I agree with the first point but have challenged both of the other two. In the process, I forgot that you had explicitly set aside (3) and only tentatively accepted (2). I’m sorry for mixing up your view with others.
Of the three “obvious facts” you posted, I agree with the first. I somewhat agree with the other two, but I’m reluctant to use those statements as a starting point. By focusing on those features of the total ages we can calculate, we miss some interesting features in the actual numbers given in the text. So, I’m going to respond to your first post where you asked for other ways of understanding the numbers:
I agree that generally a long life would be some form of honorific. But an even greater honorific (or statement of importance) would be to receive round numbers or a significant number. This is a major difference between our culture and ancient cultures. For us, when we get to something important we tend to use more precision. Round numbers are fine for fluff, but what’s important should be precise. Genesis shows the opposite mindset. For relatively insignificant people, Genesis uses numbers that appear precise. But numbers for important people seem rounded or obviously significant:
- Adam: 130 + 800 = 930
- Enoch: 65 + 300 = 365
- Lamech: 182 + 595 = 777
- Noah: 500 (sons), 600 (flood) + 350 = 950
- Shem: 100 + 500
- Serug: 30 + 200
- Abraham: 175 (5 × 5 × 7)
- Isaac: 180 (6 × 6 × 5)
- Jacob: 147 (7 × 7 × 3)
- Joseph: 110 (5 × 5 + 6 × 6 + 7 × 7)
Aside from Lamech and Serug, we probably recognize these individuals as significant. The numbers given to them confirm their significance.
While significant numbers have a purpose in highlighting significant people, the rest – the precise numbers – seem to be chosen to establish wider patterns. In Genesis 5, the overall pattern seems to be lives just under a millennia long. Sons are born between ages 65–187. But the flood, in which Noah and his sons are the only males saved, poses a problem to this pattern. With people living so many centuries after their sons are born, you’d end up with many ancestors alive at the time of the flood. If they are killed by the flood, you’d end up with a pattern of diminishing ages leading up to Noah. It would seem like Noah’s ancestors are among those judged by the flood.
To solve this, Noah lives an astounding 500 years before his sons are born. This moves his sons several generations beyond his ancestors, giving those ancestors time to live long lives and die before the flood. His father, rather than dying in the flood, lives to a numerically significant 777 years to show his shorter life is not a judgement. And the one person who dies in the year the flood also doesn’t seem to be judged by it, since he – Methuselah – has the Bible’s longest lifespan.
After Genesis 5 and its 900+ lifespans, Genesis 6:3 reveals that God set the human lifespan to 120. The Genesis 11 genealogy shows the transition. In this genealogy, with the exception of the endpoints, sons are born between 29–35. Shem needs to have his son much later, since after his sons are born Noah lives 100 more years before the flood comes. Shem’s son at 102 (going by the other numbers) is rounded to 100, since as a significant figure all of Shem’s numbers are rounded.
For whatever reason, total ages aren’t given in this genealogy as they are in Genesis 5. It only gives the age at son’s birth and the years lived afterwards. Since the age at son’s birth stays flat (except the endpoints), this means the decline is portrayed through the numbers for years lived after the son’s birth. Looking at these numbers, there is a clear stairstep descent.
The text doesn’t tell us the years-after-sons for Noah or Terah, the endpoints. But starting with Shem, the numbers given are 500, 403, 403, 430, 209, 207, 200, 119. This is a pretty obvious stepwise decrease by hundreds, ending right around the magic number of 120. The biggest jump is right in the middle with Peleg (reinforcing a theme from the text about the earth being divided in his day).
Of course, when you add the age before the son’s birth, the total ages no longer hover just above the century lines or end close to 120. Also, Shem’s unusual 100 years before his son (to keep the males on the ark to 4) bumps his total age higher, creating a steeper decline at the beginning. But if we’re looking for patterns, I find the numbers given in the text more significant than numbers we can calculate.
In sum, the rounded/significant numbers mark out important characters, and the remaining numbers flesh out patterns that reinforce messages given in the narrative: the longevity of Seth’s godly line, a decline in lifespan to 120, a division at Peleg. Given the apparent willingness of the author to mold the numbers into patterns, I see their truth value in reinforcing themes from the text, not revealing historical facts.