I always wondered why the biblical folks in Genesis lived so long. Adam, 930 years, Methusela, 969, Seth, 912, Jared, 962, and so on. Then folks born after about 1750 B.C.E. started living only as long as we do.

Was there some virus that caused people to die early? Did God decide that people were living too long and the world would get crowded? What phenomenon could cause this sudden biblical gerontological phenomenon?

I think that I have figured it out! Around 1750 B.C.E. the Babylonians invented the place value system for representing numbers. This is used today in the way that we organize our numbers. Issac was in Canaan at that time and it is reasonable that the system was picked up before the Jews went to Egypt around 1700 B.C.E.
1 means a single item, 2 is a pair, and so on up to nine. Once we get to nine, we have run through the base of our number system and move up a notch positionally and write 10. this means 1 X 10¹ plus 0 X 10⁰. Eleven means 1 X 10¹ plus 1 X 10⁰ and so on. The Babylonians in the process also invented the digit zero, which is necessary to write numbers this way.

People could now count, and write large numbers. What system of counting existed before the Babylonian system? The Egyptians had the earliest system of counting for commerce which worked similarly to Roman Numerals. This sytem, developed sometime in the fourth millenium B.C.E. was very cumbersome for counting large numbers. The representation for 969 (Methuslah’s reported age) has 24 symbols. When a carry takes place, one new symbol is written and nine, eighteen for a double carry or twenty seven for a triple carry are erased. How often did the carry get made and the erasure fail to obliterate all the lower value characters?
Additionally, people back then had no concept of era; there was no uniform system of dating. The earliest books of the bible were passed on verbally from generation to generation. Since the earliest narrators of the bible could not count (those before 3500 BCE at least) and those between 3500 and 1750 had only a very arcane system to record numbers, known mostly to traders.

The earliest books of the bible were passed on orally, and the Egyptian system is written. The symbols simply don’t relate to being spoken as numbers – just as the roman numeral LMXXVIII does not translate in the mind to 978 without active effort.
Anyone who can concieve that adding up the “ages” of all the begats in Geneisis recons the time from Adams’ expulsion to Christ is adding inaccuracy to wild guesses, to fuzzy memories, to wishful thinking. Sixty one generations from Adam to Christ is hard to swallow, since there are many more generations of kings in other chronologies for the “same period” (assuming the “begats” refer to actual persons and not to dynasties)

There is simply no reason to think that the Bible actually says that Jewish leaders lived twenty times longer than all the other people on the earth, and that Jewish leaders born after 1750 B.C.E. were suddenly killed off by God in the prime of their lives.