URCall: Time to Double

From the ICR’s URCall series of videos, hosted by Markus Lloyd. “How did we reach 7 Billion people?” (link)


How can we have a world population increase to over seven billion people today from only eight survivors from Noah’s flood, if the Earth is only a few thousand years old? Let’s assume one male and one female marry, and had children, and all their children marry and had children, and so on. Let’s assume, conservatively, that every 150 years the population doubles. After 32 doublings, or 4800 years, the population would reach almost 8.6 billion – which is more than we have now. On the other hand, if modern humans started 50000 years ago, at the same conservative population growth rate, even considering death rates, famine, wars etc, all the people could not even fit on the Earth. So if humans had really been around for millions of years, where did everybody go?

Let’s take a look at the equations. The ICR’s gloriously simplistic model can be written like this.

Doubling formula: Starting population * 2 ^ (Time / Doubling time) = Target population

Or, if you prefer symbols:

Doubling formula with symbols: P0 * 2 ^ (t/d) = Pt

If you read through the numbers given by Lloyd you’ll see that the ICR is saying that, under their YEC scenario:

YEC doubling: 2 * 2 ^ (4800/150) = 8589934592

The numbers technically check out, but note that they use a starting population of 2, rather than 6 (Noah’s children and their wives – Noah and his wife don’t count because they already had children). In addition, 4800 years is not a typically quoted amount of time since the flood: it seems to have been chosen only to make the numbers clean. More common figures that I have seen range between 2000 and 2500 BC (4000 – 4500 years ago), but we’re only talking about a world changing even that affected the entire globe – we can’t expect them to have any idea when it happened, can we?

It should be obvious that the numbers are quite malleable: if their holy book told them that it happened more like 2000 years ago, all they would have to do would be to drop their “conservative” 150 years per doubling down to around 50, and replace that two with the more biblically accurate six. But the question they were answering – if anyone was asking – was if it was possible to reach 7 billion from just eight (or six). And if you ignore the fact that the second generation would have to commit incest, along with various other problems, it works.

But then they try to turn this around and attack people who don’t believe in a young Earth, which is pretty silly.

Doubling over 50000 years: 2 * 2 ^ (50000/150) = 4.409 * 10^100

Substituting 50000 in instead of 4800 the answer comes out at about four and a half googol – which is comfortably more than there are atoms in the universe, let alone places for them to stand. The situation is reminiscent of a 1962 short story by Frederik Pohl called The Deadly Mission of Phineas Snodgrass, in which the titular character brings 20th century medicine back to 1st century Rome, and we follow what happens from there.

By the middle of the sixth century the 600,000,000 square miles of land surface on the Earth were so well covered that no human being standing anywhere on dry land could stretch out his arms in any direction without touching another human being standing beside him.

(100 Great Science Fiction Short Short Stories, 1978, page 63. I’ll not spoil the ending for you, but it goes on like that for another page.)

But if the population is always just doubling in a certain number of years, why would giving Romans medicine change anything? The answer of course is that the ICR’s model has very little bearing on reality. If there are too many people than the Earth can support then there will be no more people – and for a lot of the last 50000 years the number of people that could be fed was quite small. We only made 7 billion because of modern farming technologies, and of course modern medicine.

A case in point: bacteria are much smaller than us, but they can double their population much faster. Given a doubling time of, say, 2 hours it’s not hard to calculate that they could overrun us in less than a month. I can’t prove that the Earth is older than this – just as you can’t prove it wasn’t created last Thursday – but if it is, “where did everybody go?”

6 thoughts on “URCall: Time to Double

  1. Lol, by this same silly formula, put it this way:

    take the time difference between Ussher’s global flood, 2348BC, and the exodus, supposed to have occurred on 1446BC. Only
    900 years passed from the Flood, to this date so substitute this in the formula

    total population = 2*2^(902/150) = 129 people in the entire world.
    Yup. Sounds legit.

    And there were supposed to have half a million Israelites leaving Egypt……

  2. The first thing I thought was where is the rest of the data? What about infant mortality rates? What about war, disease, infertile couples, famine, flood, (of which you named a few). What about the fact that people living to 50 used to be considered old? This is just another case of wishful thinking by those who aren’t quite qualified to think.

    Then the points you and Darren H made of the math, what is wrong with these people? I guess, to a captive audience that already believes this creationist shit, it all makes sense. They just nod their heads, and walk away refreshed that they got their justification fix, nevermind it is fantasy…

    …if this gets double posted there was a glitch when I tried to comment on the preview page.

  3. This population argument was first promoted by ICR’s late founder Henry Morris years ago, and was as idiotic then as it is now. Depending on the animal group you chose for the argument, you could as easily suggest their potential reproductive rates points to an earth less than 100 years old, 1 year old, or even 1 month old (if you ignore all we know about population biology and factors that mediate and limit population growth). Many authors have pointed this out, as well as other major flaws in the argument. Lloyd must (or should) know this, even if he’s not bright enough to spot the problems himself. So it’s hard not to see this as anything but another case of deliberate deception by ICR.

  4. Could you redo this experiment, but do it for rabbits?

    Really, as a Christian (not a YEC), I find this really poorly done. It’s one of those arguments that purely on a surface level sounds like ‘wow,’ but after thinking about it at all, it clearly seems false. I wonder how much force they’d assign to this argument. Is it supposed to be one thread of evidence for the young earth or is it something the whole case can rest on?

    You’re also right about the malleability of the argument. I have found that to be the case for YEC in general: when evidence comes up, it isn’t a challenge to the theory. The reaction is simply to redact that evidence in and say one just “views it differently.”

  5. Could you redo this experiment, but do it for rabbits?

    According to this website, which may or may not be accurate, rabbits can double their population 3 times in a year – so d = 1/3, P0 can still be 2, and our target population can be 4.5 googol multiplied by 70 kg/0.5 kg to correct for the difference in size (this part turns out not to matter very much) we get the equation:

    Doubling formula: 2 * 2^(t / (1/3)) = 4.5*10^100 * 70/0.5

    This can be solved to get around 113.5 years until we are equally impossibly overrun by rabbits as the YECs believe we should be by people. Of course, after just 100 years by that model we already have more than 1090, which is plenty enough.

    (ED to fix third link)


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