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When we read the Old Testament, it’s hard not to notice the number of candles required for the birthday cakes before the Flood in Genesis 6. People lived for hundreds of years, with Methuselah being the oldest recorded human at 969 years old. We often brush past those ages with little more than a raised eyebrow, but it often makes us wonder why the early people lived so long. It also makes us wonder why lifespans dropped so sharply after the Flood.
God’s word doesn’t offer us a specific reason why, but people have come up with some theories over the years. Considering our culture’s obsession with living longer, some theories have even been packaged into healthy living marketing (especially when selling diet books). I won’t pretend to have the answer people have debated for years, but I would like to look at the likely (and unlikely) reasons behind it.
Correlation vs. causation
When researching this topic, I noticed that many people weren’t careful of distinguishing between correlation (things happening at the same time) and causation (one thing causing another). If we’re going to narrow down why people have shorter lifespans today, we need to understand this principle so that we don’t make wrong assumptions.
The best way to explain this is with an example. I recently read about a man’s wife who swore she was allergic to MSG (the tasty additive often featured in Chinese food). Without any testing, she assumed the allergy was to MSG because she felt sick to her stomach when she ate Chinese food. In her mind, it was
- When I eat Chinese food, I feel sick
- Chinese food has MSG
- People often talk about how unhealthy or harmful MSG is
- Therefore, I’m allergic to MSG
And that seems logical. However, the husband added that she changed her mind when she started reading labels of other things she enjoyed and realized that MSG is present in a surprising number of foods.
The real culprit? The wife knew she had a mild peanut allergy. Peanuts feature in many Chinese dishes, so her stomach issues were from cross-contamination.
This is the difference between correlation and causation. Someone noticed a pattern and made an assumption. She saw two dots and tried to connect them. Eating Chinese food didn’t cause an allergic reaction. It was just present when an allergic reaction to peanuts took place.
This is a common trend I’ve seen in discussions about lifespans before the Flood. People will take two pieces of data and assume they’re linked because they’re both present in the same part of the narrative. Understanding this principle can help us more easily sift through the more unlikely theories so that we can get closer to any better explanations we can find.
What it’s not
Understanding correlation vs. causation, I’d first like to discuss three more popular theories about these longer lifespans. I won’t go too in-depth but would like to give the basics of the theory and why it may not be sufficient.
God limits life to 120 years
Then the Lord said, “My Spirit shall not abide in man forever, for he is flesh: his days shall be 120 years.” (Genesis 6:3)
If we look at the current data, humans don’t live past 120 years. With that in mind, God looking at the state of the world and declaring that man’s days would be 120 years seems to imply that God punished man by shortening his lifespan.
However, this falls apart in two ways. First, people did live beyond 120 years after this. Not just Noah and his sons (who were alive when God said this), but those born after Genesis 6:3 still lived beyond 120 years. For example, look how long Abraham lived:
These are the days of the years of Abraham’s life, 175 years. Abraham breathed his last and died in a good old age, an old man and full of years, and was gathered to his people. (Genesis 25:7-8)
There were hundreds of years between the Flood and Abraham’s death, yet we still see people living far longer than 120 years. It wouldn’t be until Joseph that someone would die younger than 110 years.
The second issue is that God wasn’t making a broad proclamation about the human lifespan that He wouldn’t enforce for several more centuries. Instead, God was giving a deadline before He would judge the Earth for the wickedness discussed in Genesis 6:1-7. So when God said, “His days shall be 120 years,” He wasn’t speaking to humanity in general, but rather to those living on the Earth when He made that statement.
The correlation of God mentioned 120 years doesn’t line up with lifespans immediately shortening to that limit. Thus we can conclude that He was talking about how long He would patiently store up wrath over the wickedness of the people.
Food and natural living
There’s another belief that the pre-Flood diet allowed people to live so much longer. It wasn’t until Noah and his family departed the ark in Genesis 9:3 that God told people to eat meat for the first time. However, there’s been nothing throughout science or history that shows that an all-natural, all-vegetarian diet has any impact on our longevity, let alone increasing it by centuries.
There’s certainly something to be said about healthy eating preventing us from dying sooner, but there’s no evidence that it can extend our average lifespan beyond the norm. So the correlation of shorter lifespans occurring after eating meat doesn’t work when we observe the world around us.
The water canopy
And God said, “Let there be an expanse in the midst of the waters, and let it separate the waters from the waters.” And God made the expanse and separated the waters that were under the expanse from the waters that were above the expanse. And it was so. (Genesis 1:6-7)
I’m hesitant to dismiss this theory outright, perhaps it’s because I grew up with this understanding, but I do think its weaknesses are significant enough that we need to stop assuming it.
The theory goes something like this: In Genesis 1:6-7, God created a barrier (or canopy) of water around the entire earth. This barrier would help keep the world perpetually watered, explaining how plants could grow and thrive despite never raining. This water barrier could have had one of two major effects (amongst others). Either it protected us from solar radiation that would shorten our lives, or it gave us increased levels of oxygen, energizing our cells and allowing us to live longer.
Regarding oxygen, that would actually be less helpful. Outside of some very do-or-die medical situations, increasing oxygen actually poisons us. So the belief that people lived longer because of increased oxygen is opposite to what we can observe today.
Solar radiation seems more likely. However, we see significant issues in that lifespans didn’t immediately plummet once this canopy disappeared. After all, Noah still lived another 300 years after being blasted by this radiation. It’s possible that solar radiation slowly mutated genes throughout the generations, but there isn’t much support for it.
Lastly, the water canopy model has been losing popularity for a good reason. Beyond just the scientific issues it faces, it’s also biblically inconsistent. In Genesis 1:7, we assume that this expanse (or firmament, depending on your translation) that separates the waters above and below is simply our sky. We think that the “waters above” are a water canopy immediately adjacent to our sky. However, further reading of the creation account contradicts this:
And God said, “Let there be lights in the expanse of the heavens to separate the day from the night. And let them be for signs and for seasons, and for days and years, and let them be lights in the expanse of the heavens to give light upon the earth.” And it was so. (Genesis 1:14-15)
If we’re going to hold to the interpretation that the expanse is simply the sky within our atmosphere, then we must necessarily say that God hung the sun, moon, and stars adjacent to the earth and inside our atmosphere. And if this expanse extends beyond our atmosphere, we must also conclude that these “waters above” aren’t talking about a canopy set above the atmosphere.
This is a popular theory, especially for those who grew up learning it as a defense for a literal creation, but further examination makes it challenging, even inconsistent, to defend.
What it could be
Again, I want to reiterate that we genuinely don’t know why people lived longer back then because God is silent about it. However, we can reach some likely conclusions as our understanding of God’s intricate creation grows.
God’s mercy to future generations
An interesting theory from John Piper is that our shorter lives are God’s way of showing us the effects of sin on the world. We see hints of this as Jacob looks back at his 130 years and notices how brief they were compared to his ancestors:
And Jacob said to Pharaoh, “The days of the years of my sojourning are 130 years. Few and evil have been the days of the years of my life, and they have not attained to the days of the years of the life of my fathers in the days of their sojourning.” (Genesis 47:9)
Yet not only does Jacob remark about his shorter lifespan, but he seems to imply that those days were perhaps more difficult, and filled with more evil, than what his ancestors experienced.
This may clue us into the fact that God has allowed our lives to shorten to show us mercy in two ways. First, He shows us mercy by not allowing us to experience centuries in such a wicked world. Second, He shows us mercy by enabling us to see our short, brutal lives as a dark reminder of the far-reaching effects of sin in this world.
Disease and other realities of this world
The most straightforward explanation may be that as time has ticked on since the Flood, disease and other dangers of this world have simply taken their toll on us. Today, mutations of diseases mean that we have more things trying to kill us now than we did a decade ago. Decay and entropy have likewise broken things down more and more as the centuries go by.
Perhaps these problems have slowly been eating away at human lifespans even before the Flood, with the new world breeding various new diseases and other natural problems that took their toll on Moses and his descendants. A comparison would be how the quality of life in first-world countries dramatically affects lifespans compared to those in third-world countries. In this case, we may consider the living conditions before and after the Flood as so different that lifespans were naturally shortened.
One problem with this is that human lifespans haven’t continued to drop. We’d naturally assume that lifespans would continue to shrink as the world gets worse. Yet the average lifespan of 80 years today is similar to what we see during the days of King David:
The years of our life are seventy,
or even by reason of strength eighty;
yet their span is but toil and trouble;
they are soon gone, and we fly away. (Psalm 90:10)
It seems that whatever caused people to die sooner eventually evened itself out to an average of about 80 years. This doesn’t disprove the reality of living conditions and disease impacting our lives, especially since God designed our bodies to adapt and learn to fight off biological enemies. However, this may only be a part of the answer we’re looking for.
Genetics – Noah and Babel’s bottlenecks
This may be the most convincing explanation for the shortened lifespans after the Flood. Of course, it seems natural that it might be the most difficult to understand. I’ll start by explaining how Noah and Babel created two “bottlenecks” in the human gene pool, give a simple explanation of how it explains the lifespans, then try to provide a slightly more thorough answer for those who are curious.
To explain the bottleneck, we consider two areas of the Bible when the human population reached a very narrow variety of human genes. The first was after the Flood when only eight people were responsible for filling the world back up. The second is at the tower of Bable in Genesis 11:1-9 when God divided the human population into much smaller groups of people who could understand one another. In both of these bottlenecks, flaws would likely be inherited by future generations because there weren’t enough non-flawed genes to make up for them.
So the very simplest explanation of shorter lifespans is that Noah likely passed on a flawed gene to his sons, who in turn passed that flaw on to future generations. If these genes continued to be active in future generations, they would continue to be passed on and added to even more flaws.
A more thorough explanation of genetics and aging
But how does this work? Without getting too deep into the science of genetics, we can look at how genetics explain why Noah and his sons, not the Flood itself, can explain the rapid drop in lifespans.
God designed our bodies with information carriers called genes and DNA. Genes are like building plans for each part of you – you have a specific gene that determines your eye color, hair texture, and even the consistency of your ear wax. Your DNA is like a big book that collects these building plans together.
At conception, a baby can inherit either of its parents’ genes. A child may inherit a mutated gene, which is like a damaged building plan. However, over time that mutated gene can be canceled out by future generations as thousands of varieties of genes come together to grow the population.
God also fascinatingly designed our aging process. Most parts of the human body are constantly replacing themselves, and scientists estimate that our body’s materials are no older than ten years. God accomplished this by designing our cells to regularly duplicate themselves into newer versions as the old versions grow weaker.
In theory, people should be able to live forever in this way. However, our cells don’t always do a perfect job of creating a new copy of an old cell. As time goes on, these copies get less and less perfect – like an old copy machine making worse and worse copies as new errors are added to old ones. In extreme cases, our body’s copying mistakes can even lead to out-of-control cells called cancer.
Thus, we can see how problems in our genes can lead to all sorts of issues, including dying of old age. At a certain point, our bodies just can’t create cells that are good enough to keep us alive.
A more thorough explanation of Noah and aging
This theory states that Noah had a mutated gene that caused his father to only live 777 years, followed by his son Shem living a comparatively brief 600 years. Usually, this wouldn’t be too bad since one bad gene can be like pouring a cup of oil in the ocean – there’s usually enough variety out there to keep that gene from being dominant in a population. We even see that this gene seemed dormant in Noah himself, who lived a standard 950 years.
The bottleneck at the Flood changes everything. If Noah passed a mutated gene to his three sons, the entire human population would be based on that gene. The only variety we had at that time was from Noah’s genes (passed on to his sons) or from the genes his three daughters-in-law had. It would be almost impossible for this gene not to be passed on and become active.
Thus, we see that people started living shorter lives after the Flood because Noah’s mutated gene weakened the bodies of future generations and compromised their ability to maintain a healthy aging (and copying) process.
Though not as extreme, we see a similar bottleneck of genes at Babel. When people clumped up into smaller groups, the variety in genes similarly shrank and became much more likely to pass on mutations, both Noah’s own mutation and any new ones that had developed.
Obviously, even this more thorough explanation doesn’t come close to explaining the intricacies of how God designed us. Yet, for our discussion, this understanding of genetics, mutation, and aging gives us a very likely explanation for why humans lived shorter lives after the Flood. It’s not necessarily that the Flood itself caused problems, but the smaller genetic variety that resulted from God giving mercy to either people and then charging them with repopulating the Earth.
(For an even more thorough explanation of this, check out this article)
A multi-faceted answer and final thoughts
In the end, I don’t think there’s a straightforward answer to explain everything away. I suspect that all three theories we’ve discussed played a part in the pattern we see in the Bible, and the average age we’ve struck to as our genes have regulated themselves.
Mutated genes offer a clear explanation of the downward trend we see through the ages recorded in Genesis. We also can’t discount that as our genes weakened, disease and other biological problems continued to multiply. Yet, we can never forget that our God is sovereign over His creation, and no bad genes or fatal diseases developed because God wasn’t paying attention.
If half the people on the ark had a mutated gene, then we trust that our good and perfect Heavenly Father decreed it to be that way for a reason. Perhaps it was to show us how far-reaching the effects of sin are, or maybe it’s to spare the world from being filled with people who could spend centuries fully indulging in their depraved desires. We can only guess at His plans, but we know they were His plans.
Although this is a fascinating thought exercise, let’s never forget that whether we live 80 or 800 years, all of us are mortals with an eternity waiting for us after our death. We can spend all of our time, energy, and money trying to stall the effects of sickness and aging, but we can never outrun the reality that we will die. We can either look forward to death with the hope of eternal life through Jesus Christ, or dread because God’s wrath is still on us. And for those of us who have that hope for eternity, let our lives reflect where we place that hope.
And just as it is appointed for man to die once, and after that comes judgment, so Christ, having been offered once to bear the sins of many, will appear a second time, not to deal with sin but to save those who are eagerly waiting for him. (Hebrews 9:27-28)
