Just The Facts, Please

It surprises people when I say that, “No, I can’t prove it to you.” Science, you see, no matter what your seventh-grade teacher told you, is not in the proving business. It’s a nuance not well understood by people or well taught. I see a lot of exuberant scientists, too, in their books, swearing that, in the next chapter they will prove it to you.

When I say this to Young-Earthers they laugh like hyenas: “See? He can’t prove it! What a dolt!” Then I ask them to prove something we all believe to be true: that Omaha, Nebraska, exists. They don’t expect that one. So let’s get it straight: science doesn’t offer proof. In science, we have facts, and we have assertions. Proof is the milieu of philosophy. Let’s look at the three.


Facts are generally indisputable observations that exist independently of the observer. I say indisputable, but you know where this goes: everything is up for debate. My writing desk is made of Honduran mahogany. Hearts pump blood. These are facts. In arguments, facts are usually the premises, the things that both parties agree on, and they are the components of scientific hypotheses and theories. But facts are not proof, and are always subject to tweaking.


Proof is the least useful of the terms. Its technical use is in philosophical logic, where it is the conclusion to a set of premises:

Sally is a mammal.
All mammals have hair.
Sally has hair.

If the premises – the first two statements above – are true, then the conclusion must be true, and you have proved your point. But technical proofs don’t have to reflect the actual world:

Sally is a gold coin.
All gold coins have green skin.
Sally has green skin.

Here the proof logically follows the premises, but it’s pure goofiness, a word salad that can trip up any first-year college student.  Here’s something from Part 2 from the National Center for Science Education regarding theory and proof:

“[Another] misconception is that scientific research provides proof in the sense of attaining the absolute truth. Scientific knowledge is always tentative and subject to revision should new evidence come to light.”

It Has to be True. I Say So: Assertions

In any conversation, including about those science, we usually use assertions. These are statements made about how facts fit together to come to an asserted conclusion. Talking to friends, we shore them up with statements like, “Now, I’m not lying here” or,“I’m not making this up, but…” These verbal codes serve to increase confidence in what we are saying. Technical talk has its own set of confidence codes. A journal abstract is a kind of academic code for “I’m not making this stuff up.” Technical writers list the number of test subjects, set out know facts, and make predictions, all to bolster confidence in their findings. This way they a staircase of step-wise assertions is built that must, by logical progression, lead to their conclusion, making a path from A to Z.

Facts, Assertions, Proof – How They Work Together

This is exactly how all science, including evolution, works. We observe facts and put together an overarching explanation based on these observations. (See Part 2 for an explanation of a scientific theory.) From here, predictions are made. We believe that mammals appeared on earth after reptiles because we don’t find mammal fossils embedded in rock strata older than where we find reptiles. Both radiometric data and comparative biology support this finding. Each time we find another example, we are more confident in our assertion. This entire framework is vetted over decades of work from people in several disciplines, and we finally come to acknowledge the fact that reptiles appeared on earth before mammals. This is how the concepts of quantum theory, germ theory, and evolutionary theory have developed.

It can be messy. This jumble of descriptions, facts, proofs, and assertions are why we use specific descriptive terms. For example, one definition of species might be ‘a genetically isolated reproducing population’ which sounds much the same as ‘like animals having sex,’ but the first description contains reams of tacit background information that the second doesn’t. This language isn’t used to sound smart or to confuse people though that is a common charge that’s not always wrong. It’s a way to put a fence around a statement and pack as much information into it as we can. It’s a way, too, to define what we are not saying. Biology is rarely a black and white endeavor. Some people hate this. If you find exceptions to the rule bothersome, I suggest a career in chemistry or engineering. Those are sciences of yes or no, of black and white. There are exceptions to every statement in biology. This, I think, argues for evolution in that all life and every ecosystem is in constant flux. Every genome is different and changing. Every ecosystem differs this month or this year from the last observation.

A Possibly Wrong Parenthetical Observation

I take an aside here with my own observation based on my work in science. Not sure if it’s a fact. Within this messy jumble of definitions, I find science-minded folk to be generally comfortable with not knowing. It’s the milieu in which science works: once a thing is figured out, the next question is always why? Researchers push against the boundary of what is known to extend into what is not. This mindset of not-knowing seems to rankle most religious people. Like a say: I might be wrong. 


This sounds cut-and-dried, but it’s not always so. People argue that prehistoric fact cannot be reliably determined, relegating evolution to a guessing game. But is it a fact that Abraham Lincoln was a US president? And that he was shot? Not a soul is alive today who personally knew Lincoln, so how can we know? We know by correlating evidence. We read the DC newspaper at the time he was shot. Was this corroborated in any Paris newspapers? We see Lincoln’s grave. We make a prediction: if Lincoln was shot and killed, we should see another person sworn in as US president shortly after Lincoln’s purported date of death. We find that all of this argues for a real Lincoln. These historical tools are the same we use for prehistoric findings and give us the same level of confidence. Evidence leads to a hypothesis from which we develop predictions that bolsters or changes our hypothesis. Natch!

Evolution is also dismissed as an invention. “You can make up whatever facts you want.” No, you can’t. Facts exist regardless of who looks at them. You can make up whatever truth you want, and you can certainly have whatever opinion you want, but you can’t make up facts. This idea of making up facts is followed closely by the statement that we all have our own truth. Again, I agree. You get to make up your own truth. But you don’t get to make up your own facts. You can interpret how a fact fits into your worldview, but, as they say, the facts remain.

As you dig deeper into evolutionary studies, and if you bump into Young-Earth Creationists along the way, you’ll see that facts are usually the issue. You might think, and I might think, that radiometric dating is the bees knees. It’s based on solid methodology and uses simple math. But it’s an issue. Certain Christians calculate the earth to be about 6,000 years old based on genealogies listed in the Hebrew Pentateuch. Starting with this fact, they toss out radiometric dating as inherently mistaken. So what you think of as fact, they deny based on the primacy of their religious fact.

Science and Religion

What is the difference between a scientific fact and a religious fact? Aren’t they the same thing? No, and there are two keys to understand: source and objectivity. On my desk is a piece of fool’s gold. We can look up the definition, and I’ll guess the clump weighs fifty grams. These are characteristics about this particular chunk of rock that exist apart from me, the observer. And my observation can be verified by anyone with the right tools who knows how to use them.

Contrast this with a religious statement: Jesus saves people from drug addiction. While true that many people quit using drugs when they become Christian, it’s also true that many non-Christian people quit using drugs. It’s also true that many Christians use drugs. There is simply no way to measure this statement scientifically. And how would you set up an experiment to test your theory that Jesus can save people from drug addiction? How would you isolate the variable? And however strongly you believe the statement to be true, I can find ten people who disagree with you. This assertion simply doesn’t approach the rigors of fact and scientific inquiry.

This doesn’t mean that if something can’t be sifted and sorted scientifically then it’s got to be bunk. Science, I think, works great for the natural world but seems pretty useless for things like art and writing.  Attempts have been made to parse and reduce those disciplines into scientific language, but they usually falls flat. This might be because we don’t know enough yet and might be because science is good at describing nature and because the emotional human mind is best for describing art. You can go on all day long about the chemistry of the pigments DaVinci used in the Mona Lisa, but, for me, that doesn’t in any way tell me the slightest thing about her smile.

Come back for the next post when we will look at the most powerful tool for good ever invented – the scientific method.