An indisputable fact?

This Geological Society Special Publication summarises historical and current thinking on the age of the Earth; free download here

The age of the Earth is around 4.55 billion years. Is this an indisputable fact? How would you answer a creationist who asked you this? I ask for a reason.

I was recently emailed by a stranger who wrote:

I am a college student taking Geology for the first time and there is a debate amongst the students in class. I am contacting you to assist in settling this dispute regarding the age of the earth.

If given the choice between these two rudimentary statements, would you say that:

(a) It is an indisputable fact that the earth is [around] 4.55 billion years old.

or

(b) Based on current scientific evidence, the earth appears to be 4.55 billion years old; however, future generations may find evidence that has the potential to either substantiate or refute our current model.

I replied:

Excellent question. But the answer MUST depend on the threshold for disputability.

Do you think it is an indisputable fact that the Romans invaded Britain? If so, you must say that it is an indisputable fact that the Earth is around 4.55 billion years old.

If you say that this age of the Earth is disputable because, in principle, further evidence might make us change our minds, then you must also say that it is disputable that the Romans invaded Britain.

People often say that this or that scientific fact is uncertain because it is always in principle revisable. But the same is true of ALL our knowledge about the world.

Does this help? Please let me know how this plays out.

I am not satisfied with my answer.

Roman mosaic, Fishbourne, 1st Century CE; click to enlarge

The question uses the rhetorical device of the false dilemma. If I say that the age is indisputable, I am violating the principle that scientific knowledge is open to challenge by new evidence. If I say that it is disputable, the questioner has succeeded in driving a wedge, with scientific orthodoxy on one side, and me on the other, alongside Young Earth creationists. This of course is the entire purpose; people don’t go around asking whether the existence of atoms is indisputable. By refining the issue as I did, I have slipped between the horns of the dilemma. Sound logic, feeble rhetoric; looks like I’m wriggling when faced with a straightforward question.

What else could I have said?

Mosaic, Fishbourne, image by Charlesdrakew – Own work, Public Domain, https://commons.wikimedia.org/w/index.php?curid=4755271

About Paul Braterman

Science writer, former chemistry professor; committee member British Centre for Science Education; board member and science adviser Scottish Secular Society; former member editorial board, Origins of Life, and associate, NASA Astrobiology Insitute; first popsci book, From Stars to Stalagmites 2012

Posted on June 10, 2017, in Education, Science and tagged , , . Bookmark the permalink. 19 Comments.

  1. Anything can be disputed , and what we accept or dispute will depend on our view point. If we start with an assumption such as creationism we will doctor the evidence to prove our beliefs. Science has been built up without making assumptions but by looking at evidence. So when considering things like the age of the earth or indeed the age of anything the best bet of any equirer is the scientific answer.

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  2. Michael Fugate

    One could always 1) ask for an alternative number, if 4.55M is not true and 2) ask for the individual’s understanding of the issue – what is the evidence for an age of 4.55M, what is the evidence against it? What evidence would convince the individual that the age is 4.55M?

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  3. If one is interested in how old the Earth is, “about 4.55 billion years” is a pretty good estimate, the best that we can give right now. (I have to look up the answer in a recent resource. I’m not a scientist. I wouldn’t be surprised to hear a number differing from that by even as much as a billion or so years.) Does anyone have a better answer? If one wants a more conservative answer, “of the order of magnitude of billions of years” (that is, more than 1 billion and less than 10 billion years), including some major surprises. Going far beyond that: “more than a million years, but not eternal”. Beyond that, we’re in the realm of speculative philosophy, where “Last Thursday”, “eternal return”, “is there a real Earth”, etc. are logical possibilities.

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    • We’re good to a few hundredsof millions of years, and even to the point where we can refine the question: formation of solar system, formation of earth, subsequent formation of Earth-moon system, melt-down of arth’s core.

      Liked by 1 person

  4. John Wiltshire

    I have had this kind of discussion with many of my Creationist friends and I point out that the meaning of terms like “indisputable” needs to be agreed before they are used as notational shorthand in any meaningful discussion. If shorthand is not agreed then conversations become pointlessly cumbersome and tangled.

    I argue that levels of probability should be included where possible. Terms like “compelling evidence”, “well substantiated” , “beyond reasonable doubt” etc. imply a high probability and I use such terms instead of absolutes like “indisputable” which, in the absence of an agreement about shorthand semantics, are likely to be exploited and weaponised by the Creationist mind-set.

    The question can also be inverted by asking the Creationist for an estimate ( starting by stating which side of the 50/50 mark) of the probability that the scientific view is wrong and what evidence they have for that view?

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  5. The problem is the ambiguity of “uncertain” (or “indisputable”). When we say that science does not claim certainty, we mean that all current understanding is in principle revisable. But in everyday usage “uncertain” means “in doubt”, which is a different concept. The questioner exploits the ambiguity in order to diminish science (he hopes) to the same level as ancient religious ideas. It is a tactic that the supporters of science and rational thinking have to be on the lookout for.

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  6. i often say it is indisputable that the earth is billions of years old and the universe a lot older. The age of the earth has hovered around 4.6 billion for 70 years so is very secure.

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  7. I would say option B, with the caveat that it is as unlikely to be changed beyond the current margin of error as it would be to conclude that matter is not made of atoms (thus keeping it to a more related topic). As you say, people don’t dispute their existence.

    Alternatively, you could agree that, while it is, in principle, disputable, no one has ever found a valid reason to dispute it beyond the current margin of error, and that margin of error is so tight that it is exceedingly unlikely that anyone ever will.

    This is more or less what your answer does, but perhaps by making it as wordy as it is and comparing it with an unrelated topic, it might be read by an unscrupulous quote-miner as expressing doubt over the age of the earth.

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  8. You are more subtle than I would be, though I’d have trouble agreeing that this is an “excellent question.” This is one of those false choice questions (right up there with answering “So how often do you beat your wife?”) designed to make the respondent seem stupid and seeming to pose a false dilemma. So I’d stop well before answering and question the choices: they are not complements and do not fully encompass all possibilities.

    To me, the key is the word “refute” in the alternative, which is pretty misleading. We aren’t ever going to *refute* the idea that the earth has an age; the most we will do is *refine* that age. How much evidence would it take to refine that age? If refining it from 4.55 to 4.56, not very much because the uncertainty on the existing data is weak at that scale. But 4.55 Ga to 3200 yrs? Gosh, it is hard to even begin to imagine how much evidence it would take.

    What I have noticed is that creationists seem to think that scientific theories fail on a single observation, when the reality is more like a US civil trial, where it is a preponderance of evidence. (This is why competing hypotheses are helpful, as otherwise the single existing theory, whether it be geocentrism or neptunism, will always have a preponderance of evidence). So you get this “refute” terminology implying one observation will overthrow everything. Look, in theoretical math this will be true, but not in the natural sciences.

    So in short, I don’t have a more nimble piece of rhetoric for you. About the best I could do is play the same game backwards: “Is God cruel? or is He not omnipotent?” Yes, it is insulting and would produce sputtering about how the choice is false, etc., but it is the same kind of crappy logic.

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    • Indeed. I’d missed the interesting fact that W”either substantiate or refute” is itself a false dilemma, based on the vulgarisation of falsifiability that I discussed in my last post.

      Though (unlike some gnu atheists) I try to avoid any entanglement with religious questions, which I see as playing into our opponents’ hands.

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      • I just used a religious example (much as you used a historical one) because it carries you into terrain the questioner might find both familiar and uncomfortable the same as you find the original question. I would think most Christians would have wrestled with that dichotomy long ago (how many sermons include “God moves in mysterious ways”?) and felt comfortable refuting it by saying the question is unfair–in other words, not intended as a challenge to their religion, but a challenge to their logic, which is what we seek. Their response then provides you with the demonstration of how their original question was equally misleading. But as I said, not nimble rhetoric. Good on you to respond carefully and thoughtfully; it is easy to (want to) ignore such requests.

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  9. What else could I have said?

    “Turtles. Turtles all the way down.”

    It’s the go-to answer to Creationists.

    Liked by 1 person

  10. A clearer view of the context or of the student might alter my view. However I think it is a trick question to some degree. Either/or never really works. It is not how science proceeds. Have you stopped beating your wife comes to mind. One can pretty well prove that the earth is more than 6000 years old. Equally it is indisputable thatfurther observations and research will refine our understanding and knowledge. One need not fall into this false dilemma nor feel obliged to use the same terms In replying.

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    • You have very clearly restated the problem, which is, how to challenge the false dichotomy without seeming evasive.

      As for the context, I inferred that some students, under creationist influence, were posing this question. The student had come across my own writing, and, while properly appearing neutral in his letter to me, was looking for help in rebutting them.

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  11. Although occasionally there are minor adjustments to the age figure, a future massive relative increase or decrease appears unlikely – so I personally think (a) is fine though maybe with the phrase ‘scientifically’ indisputable.

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