Historical Science: How do We Know a Fish Fossil is a Fish Fossil?

The difference between what young earth creationists like to term “operational” or “observational” science and historical science doesn’t have the sharp distinction they like to project to their audience.  I was reminded of this recently when I had an opportunity to hear Tommy Mitchell speak at a local Answers in Genesis conference a few weeks ago.  One particular talk was entitled:  Jurassic Prank:  A Dinosaur Tale.  In it Mitchell presents the young-earth case that dinosaurs lived with man as recently as a few thousand years ago.  The “prank” of course is that scientists have been telling us that dinosaurs died out millions of years before man existed.  You could say the punchline to the entire talk was that the public has been punked with regards to the truth about dinosaurs.

There are many lessons to be learned from this talk but I want to focus on one seemingly simple observation that Mitchell makes.  Below is a YouTube version of nearly the same talk but this one was recorded over two years ago (2017 update: that video was deleted a few months later, I found another recording of a presentation from another date which includes the same commentary).  If you forward to about the 15 minute mark you will hear Mitchell talk about how we know things in the present but we can know little to nothing about the past.

The example he uses is a fossil fish.  He asks what we can know about the fossil on the screen. The answer: Its dead, and it’s a fish.   He claims this is the extent of what you can know about this fish.

He is going to go on to claim that we dig up fossils in the present and we can’t know much about their past such as their age, what color they were, what they ate or how they behaved etc.. To most audiences this sounds reasonable.  But let’s stop for a moment. I want to back up a bit and ask what might sound like a silly question.  Just how does Tommy Mitchell know that the image on the screen is a fish?  He stated it was as if this was an unassailable fact and not subject to interpretation.

He introduced this part of his talk by making the claim that what we know is that this is a “dead fish.”  Did he see the fish when it was alive? Did he see it die? Did he see it become fossilized?  Did the fossil come with label saying it was a fish? Did it even come with a label saying it is a fossil? The answer is No to all of these questions.  So how can he be absolutely confident that this is, first, a fossil, and secondly that it is the remains of a dead fish?

I am not suggesting he is wrong. In fact I am quite sure that this fossil does represent the remains of what was once a living fish. But Mitchell’s own definition of historical science precludes his high degree of confidence that this is a fish without accepting that we can actually know things about the past and we can know about the past by our observations from the present world.

How so?  The only reason he believes this is a fish is because he has observed fish skeletons in the present and he has inferred that similar arrangements of minerals in the shape of bones represent the remains of a fish in the past. This use of the present to infer the past is a hallmark of one means of doing historical science.  It seems trivial to question the “fact” that this is a fish fossil but only because it is obvious that this is exactly what it is. But it is an inference—an interpretation—of evidence not a fact.

Mitchell has never seen the original fish that came to be this fossil. In fact he has probably never even seen the original fossil. He can’t know this is a fish without a working knowledge of the anatomy of fish today and a series of logical inferences.   His inference is by far the most reasonable hypothesis as to what the origins of this assemblage of arranged minerals must be. But it isn’t the only hypothesis.  The reason this hypothesis is compelling is because of our common experience with fish. However, if Mitchell’s had not experience with fish in his life and he were shown a picture of these fossilized bones would he immediately proclaim that this was a dead fish? Probably not. He might say, we can’t know anything about what this was. But if he studied the world and then discovered the characteristics of animals we call fish suddenly he would realize that we can know something about these dark impressions on a rock.

Knowing something about fish today, wouldn’t it sound silly if I were to argue that this fossil is not actually a fossil fish at all? What if I were to argue that they really are just a random collection of various minerals in the rock that resemble the bones of a fish. These mineral pieces were just swept together in a flood and just happened to be arranged such they appear similar to a fish.   You would say that, although not impossible, my hypothesis is so unlikely that this isn’t a plausible explanation for the origin of what we see and thus you would reject it.

But for scientists who study the earth the evidence for an old earth is as obvious as a fossil that appears to be a fish.  In addition, scientists who study Earth’s history find the arguments for a young earth, such as the how the fossils came to be arranged as they are in the fossil record, are as silly as my hypothesis for how that fossil that looks like a fish isn’t a fish.

Why is Mitchell so sure that the fossil he shows was fish but that we can’t know anything else about this fish?  I would submit it is because he doesn’t know what he doesn’t know.  As I pointed out above, he only knows it’s a fish because he is familiar with the evidence that would allow him to infer that this is a fish.  Mitchell thinks we can’t infer anything else about this fish because that would be doing historical science but he isn’t familiar with the evidence and ironically he was using historical science to get him to the point of what he thinks he knows.

Someone who is very knowledgeable about oxygen isotopes might be just as confident of the environmental conditions the fish lived in as they are that the fossil represents a fish. If the fossil is found in volcanic ash, we can infer how long ago that ash layer was formed by observing the ratio of radionuclides in the ash layer and thus determine the age of the fish as surely as we can determine the age of bones found in cement if we have evidence that the cement was poured in 1967 even if no one today actually observed the body being thrown in the cement.  We can know more than just this is a fish and it is dead.

Nothing I have said is particularly novel and I have even written about this before (Historical Science and the Case of T. rex’s Puny Arms).  The point is that often the “truth” is obvious to us when we can quickly infer from our common knowledge of present day animals what must have been an animal in the past.  We think we are doing “observational” science and we quickly accept these things to be true. Earlier in his talk, Mitchell claimed that dinosaurs obviously existed because we have their bones. Here again he made an inference from the present to interpret the past.  It seems trivial but YECs need to acknowledge they are inferring the past through their observation of the present and they are coming to firm conclusions about the past that they believed based on evidence.   The difference between what YECs like to term “operational” or “observational” science and historical science doesn’t have the sharp distinction they like to project to their audience.


Here are a few fossil fish (and stingrays) that were on display at Fossil Butte National Monument in Wyoming. These were all collected in this location and my family and hiked to a quarry and witnesses NPS employees cutting more fossil fish from the rocks. (see my post:  A visit to Fossil Butte National Monument for more pictures)

11 thoughts on “Historical Science: How do We Know a Fish Fossil is a Fish Fossil?

  1. As far as I can understand, the YEC “observational science” idea is just collecting facts and not making any predictions. What really baffles me about this is why they then feel so justified being skeptical about the past, but seemingly so confident that things like gravity will work 5 minutes from now. Isn’t telling the future a greater feat than discerning the past?

    Liked by 2 people

  2. Reblogged this on Primate's Progress and commented:

    Creationists argue that historical science is different from, and more uncertain than, present-day observational science. But their choice of examples shows that they themselves don’t really believe this.


  3. Of course, long ago fossils were thought to be things grown in rock. One of the key observations that Steno made was that the fossil bones had the wear marks created by living organisms (he was one of the great anatomists of the day; people would come to watch him conduct an autopsy of some creature). That recognition carried the day for him; prior to that the observation that some fossil resembled a fish or some other creature was not, in and of itself, proof that it really had ever been such a thing. So several hundred years of geological work has at least carried the YECs past where folks were long ago, even if they don’t recognize it.

    Liked by 3 people

  4. The one thing you point out is that in order to state any theory based on a set of data, you must make some assumptions based on personal biases. This still makes a case for skepticism in general of the legitimacy of Darwinian evolution, and specifically skepticism of the legitimacy of more complex lifeforms evolving from simple lifeforms.


    1. That’s true for all of science, and all scientists are skeptical of their own work and that of others. All science is inference from the available evidence, and it’s why scientists are so rigorous about methodologies in order to avoid personal bias and/or to test this possible bias via another source to make sure that inference there is the same.

      Liked by 1 person

      1. Very true of pure science. However, that which is presented in K-12 “science” text books is stripped of all skepticism and self-examination. It is better described as scientism propaganda.


  5. Once in a while I make the mistake of watching a little of the Answers in Genesis program. Usually, just a few seconds of those smug, gleefully ignorant Pharisees infuriates me into a bad mood that lasts for the rest of the night–if I am lucky!
    I keep asking myself, how can they be so dedicatedly wrong? The best I can figure, it really is a spiritual matter, and they are among those who may well be told by God to “Depart from me, evil doer”. I don’t know.
    In my experience, these YEC promoters study just enough current science to know what to twist and defraud to the public. They know they take things totally out of context, and they libel and insult people with understanding. At some point, they have to know they are frauds.


    1. What’s remarkable is how effective they are at training Christians to ape (pun intended) their terrible arguments, even when using arguments that are mutually contradictory. During a recent discussion at /r/christianity, I engaged with a creationist who started by claiming that scientists had lots of “anti-creation theories” that lacking any real science. When I pressed him, he claimed that anything in the past, like the Big Bang and evolution, couldn’t be tested and wasn’t science. (He also trotted out the claim that the 2nd law of thermodynamics disproved evolution.) When I showed him how science had made successful predictions about evolution and the Big Bang, he doubled down and claimed science could only make physical tests of things in the present. When I provided a definition of science (from a link he provided!) that science included investigation of the past, he abandoned his tactic altogether and accused me of having faith in science.

      There are people like this everywhere. Not an original idea in their heads, simply repeating what AIG tells them about about the past not being open to investigation by science. In addition to being wrong, this is pure casuistry. Even a phenomenon occurring in the present immediately becomes the past once it has happened. Whether five minutes ago or five million years ago makes no difference, as long as your methodology is sound.

      Liked by 1 person

Comments are closed.

Up ↑

%d bloggers like this: