Pointing out how completely illogical and unscientific are creationists is something I need to do on a regular basis here. A creationist who regularly trolls the SGU Facebook page recently posted this video, which is a great opportunity to meet my creationist debunking quota.

Like all creationist propaganda, the video does not make any serious or legitimate scientific points. The purpose is just to provide a plausible screen for denying one of the most solid scientific facts every established – that life on Earth is the product of organic evolution.

The video is a collection of “gotcha” ambushes of students and scientists, asking them loaded questions that defy a simple answer (because first you would have to unpack all the false assumptions in the question itself). It’s natural to pause after such a question, while considering how best to approach it. The segments often cut out after the initial partial response followed by a “gotcha” follow up statement by the interviewer.

This is a sleazy style not amenable to serious scientific debate or discussion, so perfect for creationists. In any case, the video has one major point to make. It starts with a quote:

A scientific method is based on, “The collection of data through observation and experimentation…” – Science Daily

I like Science Daily as an aggregator of science news press releases, mainly because they are one of the few outlets that provides a link to the actual paper. I don’t think that makes them an authoritative source on the philosophy of science. I am also always suspicious of quotes ending in, “…” – it always makes me wonder what is being left out.

In any case, the snippet is fine as far as it goes, but it is certainly a long way away from a complete description of scientific methods. Collecting data through observation and experimentation is one method of science, but it is not the core feature. You can collect data without doing science, and you can do science without collecting data. If I had to give a quick summary I would say that science is a set of methods for empirical hypothesis testing. I think the key is that whatever you are doing it should be able to either support or refute some testable hypothesis about how the world works.

There is a reason creationists focus on this somewhat superficial definition of science (observation and experimentation) – because they then argue that you cannot observe evolution happening right now, or run an experiment in which evolution happens. Therefore, evolution is based on faith.

Don’t bother rebutting them (as many in the comments do) that belief in God is also based on faith. They know, and they are OK with that. Their point is that both are based on faith, so what are you going to have faith in, God or an evolutionary fairy tale made up by people? (I know, this just begs the question, but they also have no problem using logic that assumes their faith is correct.)

That is basically the video, asking people for direct observational evidence that evolution is real, and then rejecting all the offered evidence because it is in the past. No one was there to see evolution happening millions of years ago, so evolutionary theory cannot be scientific. Evolution is too slow to observe directly, so you cannot run experiments.

This is a very old creationist tactic that has (as all their tactics have) already been deconstructed many times. They are taking an arbitrarily narrow definition of science (which essentially makes it a false definition) and then argue that evolutionary theory does not fit their narrow definition.

But even under their narrow definition, at least the Science Daily quote above, evolutionary theory is just fine. Looking at fossils, stone tools, genes, population distributions, comparative anatomy, and developmental biology are all making observations. Dating sediments by radioactive decay involves conducting experiments.

It is perfectly scientific, and does not require any faith, to infer the past from traces left in the present. Recently, for example, scientists inferred that the Earth was witness to several supernovae millions of years ago (even though no one witnessed them) because of the effects of the radiation on the surface of the Earth at the time.

Of course all of history is only known through the evidence left for us to observe in the present. How do we know the Aztecs existed? How do we know George Washington existed? Have you ever spoken to him? The fact that people were around to observe George Washington is irrelevant – no one alive today met him. We still only have historical records.

What creationists do is deny the legitimacy of all historical sciences. The like denying the legitimacy of any science, because then they can fill in the gaps with their faith-based narrative. Their logic, however, is transparently invalid.

Some of the ambushed scientists in the video pointed out that we actually have observed evolution happening in the lab. The many decade experiments of Richard Lenski documented significant evolutionary changes – direct observational and experimental evidence of evolution. This is undeniable, but of course creationists still deny it.

Here they shift to another old chestnut, that this kind of evolutionary change is just “microevolution.” It’s not “macroevolution” of one “kind” into another. There are two major problems with this line of argument, both related: there is no operational definition or even theoretical difference between micro and macroevolution, and there is no such thing as a “kind.” This is more than just a demarcation problem – there isn’t even a fuzzy line, there is no line.

For example, they dismiss the Lenski experiments by saying that the bacteria are still bacteria. Of course they are, we are talking about 30 years of evolution. Speciation events take thousands of years. There needs to be enough time for sufficient evolutionary changes to accumulate before two or more populations can and will no longer interbreed.

Even if a new species arose creationists will then fall back on their “kind” fallacy. A tiger and a lion are the same “kind” because they are both cats. Really? A house cat and a lion are the same “kind?” Why aren’t all carnivores a “kind?” Why not all mammals, or vertebrates?

This is where the “kind” idea falls apart. They are just taking one evolutionary branch and completely arbitrarily calling it a “kind.” But branchings occur at all levels, and the messiness of the branching order means that there are often outliers, like the duckbilled platypus.

When we look at nature in detail we see that there are not discrete species, there are not discrete categories or “kinds.” There is just a messy complexity all blending together. There are individuals in families, and subpopulations of populations of subspecies of species of genera of subfamilies, families, superfamilies, and on up. We keep having to add the sub and super splitting of taxonomic levels because the natural world has far more messy complexity than our clean categories can capture.

The picture becomes even more complex when we add in fossil species.

So now that the utter unscientific nonsense of the creationist position has been demolished, let me answer their so-called “unanswerable” question. How do we know evolution is real?

Evolutionary theory makes a number of falsifiable predictions, and they have all survived a century and a half of observation and experimentation. The fossil record presents an evolutionary pattern, in temporal, geological, and morphological space. Genetic analysis shows a branching pattern of relatedness among all living things. Developmental biology shows remnants of an evolutionary past. When we look at all living things today, we see features that betray an evolutionary history.

Obviously this is just a quick summary. There are literally thousands of scientific papers providing supporting evidence for the reality of evolution. What creationists don’t realize, or don’t want to acknowledge, is that what scientists have observed in the fossil record and in genetics and biology after Darwin proposed his theory was not the only possibility.

If evolution were not true, then the odds are overwhelming that the fossil evidence would have clearly falsified evolutionary theory. “Rabbits in the Precambrian” is the classic example. We might have discovered that there were distinct “kinds” with clear chasms between other kinds, that no mere gaps in evidence could fill. We could have discovered modern phyla without any possible antecedents, or impossible chimera that could only have been created from the top down.

We discovered none of those things, however. We found fossils that fill in a pattern of branching evolutionary relationships. We found genetic variation that honestly could only have arisen through evolution.

We did not have to find those things, but we did, because evolution is true.