This from post on his blog Naturalis Historia by Joel Duff (professor of biology at the University of Akron) a couple years ago concerning the mind boggling number of man-made stone artifacts poses for YEC claims concerning the age of the earth.

Source: Trillions of Stone Age Artifacts: A Young Earth Anthropology Paradox

Trillions of stone artifacts cover the surface of the African continent. The product of the manufacturing of stone tools by hunters and gathers over long periods of time, these stone artifacts literally carpet the ground in some places in Egypt and Libya.

Just how much Stone-Age produced rock could be strewn across the African continent?

Trillions and trillions of artifacts!

The trillion isnít a typo. That number sounds absolutely fantastic, doesnít it? Letís take a look at how these numbers were derived.

The results of a study just published (see references below) shows how incredibly dense stone artifacts can be in some places in Africa. Working in a remote location in southern Libya, researchers took surveys from hundreds of one or two-meter square plots. From the tens of thousands of artifacts found in them, they estimated a minimum density of 250,000 stone artifacts per square kilometer is present in this portion of Libya.

And this only included what was visible on the surface.

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Unfortunately the image doesn't enbiggen. They are several pictures of the landscape provided by "Lithic Landscapes: Early Human Impact from Stone Tool Production on the Central Saharan Environment" showing just how densely covered this area is with paleolithic stone tools. They literally carpet the ground in some places in Egypt and Libya.

Source: ibid

The researchers surveyed other published estimates of stone-tool densities in other areas of Africa. For example, some parts of the Nubian Desert average 12 million artifacts per square kilometer. They also calculate expected stone production given certain assumptions about population size and stone tool use over time. Overall, the researchers estimate that stone tool production across the entire continent of Africa has resulted in an average of 500,000 to 5,000,000 artifacts per square kilometer.

Africa is roughly 30 million square kilometers in area, so that would put the total number of stone artifacts between 15 and 150 trillion. Yes, that is trillion with a Tóan astounding number.

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Duff notes that this number seems high to him yet states that "even if the authors overestimated the number of rocks several fold, it is clear that the number of rocks that have been manipulated by human hands that lie on or just under the surface of the African landscape is enormous." He then goes on to note how a site in South Africa similarly carpeted with stone artifacts has been estimated to contain several billion stone artifacts and that is likely a conservative figure in that the identification of stone tools is a notably rigorous and very conservative process -- which tends to err on the side of counting too few artifacts rather than too many (See, for instance A Method for Identifying Stone Age Hunting Tools)

At this point, he delves into the problem that this number of paleolithic stone artifacts poses to YEC so let's return to the article

Source: ibid

The standard young-earth view holds that the ďstone ageĒ was a short period of just a few hundred years in length (500 being the absolute max). This period spans from the time when families spread out from Babel 4250 years ago to about the time of Abraham.

The Answers in Genesis conception of when the ice age occurred
after the Flood. They place the Stone Age during this time.
Source: AIG page

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The diagram above shows where stone-tool making is expected in the young earth timeline and Duff notes that this is also what the Institute for Creation Research also says

Source: ibid

Let us be generous and give the YEC hypothesis 500 years for the Stone Age. I have done a few back-of-the-envelope calculations to see how the young-earth hypothesis fits the data about the stone-age tools in Africa, as presented above.

Here are my assumptions:

  • Time span of 500 years.
  • 25 years per generation (eg. the replacement rate of population)
  • 10,000 artifacts produced by each person (male and female) in their lifetime
  • Average population size during this time: 100,000 hunters and gatherers/nomads

Now for the calculation: 20 generations x 100,000 people gives us 2 million people who produced stone tools. If each person produced 10,000 artifacts during his or her lifetime then this would result in 20 billion total artifacts, or 40 million artifacts generated per year.

Now, 20 billion artifacts in 500 years is a lot, but it is definitely nowhere close to the 15 to 150 trillion artifacts estimated to be in Africa alone. At 40 million artifacts per year, it would take a population of 100,000 individuals 100,000 years to produce just 4 trillion artifacts.

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It should be noted that his assumptions are extremely generous in that they pretty much are assuming that making these tools is all they do day in and day out.

Source: ibid

Modern science has determined that the Stone Age lasted as long as 2 million years. Assuming relatively small populations during that time span, this is about the time needed to produce the quantity of artifacts that we observe and estimate today.

Yet here is what the YECs assume. A small band of people left Babel in 2250, migrated to Africa, forgot all the technology they once had in Mesopotamia, learned how to fashion rock into tools (this is a technology itself), extracted 40 million pyramidís worth of rock from all over Africa, and fashioned that rock into countless numbers of stone tools in 150-500 years? Some YEC will doubtless claim that a group of 1000 people leaving Babel could have grown into a population of millions within 500 years and thus they could have produced several hundred billion artifacts. This still doesnít get one to the observed numbers and that population growth would be unrealistic given the very difficult life of a nomad especially competing with lions and hyenas with only stone tools.

And, remember, we are not even considering the billions of stone tools that exist outside of African in Asian and the Americas. Presumably people made their way to the Americas not long (10s of years maybe in the YEC timeline) after they came to Africa and yet the volume of stone tools in North America is a tiny fraction of what is observed in Africa.
Anyway, this group of migrants from Babel would have been small in number at first, and so it is not even reasonable to think they would have grown to 100,000 individuals by 2000 BC when they settled into an agricultural lifestyle and no longer needed to fashion stone implements. My estimate of 20 billion artifacts is incredibly generous, and yet it leaves the YECs exceedingly short of explaining the vast numbers of stone tools that are so easily observed.

The sheer abundance of stone tools in Africa is one of most devastating pieces of evidence against the young-earth hypothesis that I have encountered. Until I started looking at reports of stone artifacts in Africa I had no idea that stone tools were so ubiquitous. We see them in museums and tend to think they are very rare.

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The final paragraph notes how this demonstrates that "YEC model for interpreting what we observe in the world around has provided a woefully inadequate explanatory framework" and how YEC's attempt avoid problems like this "is why so many are apt to become disillusioned over time when they are confronted with the overwhelming evidence of their failed paradigm" (a problem that I've noted in the past, particularly in pre-Crash threads).

Generally YECs merely hand wave such things off by claiming that those bringing it up are basing their points on "naturalistic" or even "atheistic" assumptions and motivations and hence unworthy of discussion but this won't work with Duff who has a track record as a committed Christian having published in Perspectives on Science and Christian Faith and doing many lectures.

And yet, like the one trick pony they are, that is precisely the type of response that Terry Mortenson of AnswerinGenesis takes essentially claiming that if Duff doesn't agree with YECs concerning the age of the Earth he must therefore be a naturalist who rejects the authority of the Bible saying that his work divorces itself from Godís written revelation."

Mortenson grumbles about "the evolutionary scenario he so enthusiastically endorses" ignoring the fact that this has nothing whatsoever to do with evolution[1] but is essentially straight up math. Considering that the minimum estimated number of tools (15 trillion) means that more than 3 billion were produced every single year up until the modern day from the time that Noahís family departed the Ark there just is not enough time in the YEC timeline.

Mortenson then goes on to huff that "Dr. Duff needs to believe Godís inerrant Word, an eyewitness to all events in history, not the fallible and erroneous words of men who imagine events over millions of years that no human observed" essentially saying that if you aren't a YEC then you don't believe God -- a tactic we see employed around here in spades.

After this he tries to hand wave away the artifacts claiming that they really aren't man-made at all but are instead produced by all of the cataclysmic events that continued to wrack the planet "in the couple of centuries of the post-Flood" world. Of course there is no suggestion in the Bible that the world was wracked with heavy volcanic activity that blotted out the sun with ash, induced an Ice Age, or resulted in "residual catastrophism"[2] and in fact if anything this notion is contradicted (Genesis 8:21-22). But some YECs have always been quick to "correct" mistakes in Scripture whenever their precious YEC dogma is challenged. They'll pencil in whatever is needed that the original author absent-mindedly forgot to put in.

What is ironic is that Mortenson here is essentially rejecting "intelligent design" of these artifacts and is instead appealing to natural processes. He is rejecting design and promoting random chance events.

The fact is that dozens of experts on stone tool production have studied the stones from this region and they've all reached the conclusion that they are indeed the result of human manufacture. Yet Mortenson, who has zero training in this field glances at a few pictures and speculates that they must instead be the result of post-Flood local catastrophic events.

He doesn't even seem to realize while pontificating on a subject he has no knowledge of that the idea that they could have been the result of rocks bumping into each other hadn't already been considered and subsequently extensively tested and rejected.

As I noted above

the identification of stone tools is a notably rigorous and very conservative process -- which tends to err on the side of counting too few artifacts rather than too many (See, for instance A Method for Identifying Stone Age Hunting Tools)

A great deal of research has been devoted into investigating just how various natural processes can produce stone flakes and how real artifacts produced by intent can be differentiated from them.

Further, even if everyone screwed up royally and they misidentified 90% of them it would still require far too much time than the YEC timeline permits

1. In fact I discovered the article in a reprint on an Old Earth Creationist website that utterly rejects evolution

2. All things brought up by Mortenson in his flailing attempt at a rebuttal