Evolution Explained, Part 2 – What is a Theory?

Evollution Theory?

What is a Scientific Theory?

If you read evolution, it isn’t long before you’ll run into someone who dismisses the whole shebang as just a theory. What they mean it’s just a guess, a hunch. If they are of certain beliefs, they likely mean that pseudo-scientists made it up only because they hate G. Never mind that Darwin was a trained theologian: as we’ll explore later, facts don’t matter. You might as well consult the Magic Eight Ball. “Is evolution real?” “Outlook not good,” it says. The tacit argument is that there are other, and probably better, explanations. And if there are other explanations for the diversity of life on earth, shouldn’t we be responsible and air those too? If evolution is just a best guess, then shouldn’t other guesses compete?

Eight BallSo, what is a theory?

Merriam-Webster defines a scientific theory as ”a plausible or scientifically acceptable general principle or body of principles offered to explain phenomena.” This is opposed to ‘abstract thought, speculation.’
The American Museum of Natural History characterizes a theory as something that:
    “…not only explains known facts; it also allows scientists to make predictions of what they should observe if a theory is true. Scientific theories are testable. New evidence should be compatible with a theory. If it isn’t, the theory is refined or rejected. The longer the central elements of a theory hold – the more observations it predicts, the more tests it passes, the more facts it explains – the stronger the theory.”

How Do Scientists Define a Theory?

There is no single definition and no set rules for what makes up a theory. But the accepted elements of a theory are facts, observations, and hypotheses that combine disparate parts into a many-stranded whole. A theory includes most of these components:
    Well-established observations that generally occur in every known occurrence
    The theory is strengthened by new findings
    The theory is falsifiable
    The theory is flexible, able to absorb new facts
    The theory incorporates findings from several disciplines
    The theory provides predictive power for further exploration and study
Note, too, that confidence in a theory can change. Phrenology was the rage in the early nineteenth century. It is the ‘science’ of predicting moral character and intelligence by measuring the skull. There is a putative basis for the study:
1. The brain is the organ of the mind.
2. The mind is composed of multiple distinct, innate faculties.
3. Because they are distinct, each faculty must have a separate seat or “organ” in the brain.
4. The size of an organ, other things being equal, is a measure of its power.
5. The shape of the brain is determined by the development of various organs.
6. As the skull takes its shape from the brain, the surface of the skull can be read as an accurate index of psychological aptitudes and tendencies.
Given these premises, there is a logic to this science. But medicine and biology and psychology continued revealing new facts about physiology, and phrenology was seen to be a fallacy. The premises didn’t hold. New facts didn’t fit into the theory. Predictions based on what was ‘known’ weren’t found to be true. Today, phrenology is a curiosity that is tossed into the history bin.

Einstein Theory

Must a Theory Be Proved?

What does it mean for a theory to be proved? The truth is that we are never done with a theory. Every experiment or observation or equation adds to or detracts from the general idea. It’s more accurate to say that we build confidence in a theory. There was a time when serious and respected scientists measured skulls with high confidence in their ‘results.’ Did that make it true? No. Continued and further research and observation finally showed that there was no merit to the idea and it fell from use.
Nor is a theory a fact. It is an observation about a collection of facts. So it cannot be proved like a syllogism. The National Center for Science Education answers this misunderstanding with the following correction:
    “[This misunderstanding]implies that theories become facts, in some sort of linear progression. In science, theories never become facts. Rather, theories explain facts. [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.”
Haldane’s Rabbit in the Cambrian comes to mind.

Can a theory be both right and wrong? In a sense, yes. The backbone of evolutionary theory is considered fact by most biologists. But controversy abounds around the edges. This is exactly what  is expected. Science is always working at its edges. No one wonders about the circulatory system anymore or how thickened heart muscle affects the system. No one is wondering about what drives the heart to beat. We don’t work on the things we know. As soon as one question is answered, new questions are asked. This is where science sits and it’s at the edge that we often get things wrong. Why wouldn’t we? We don’t know. That’s why we study them.

Occasionally, a theory is overturned. The most famous overturned idea is the geocentric universe. It is natural to think that the sun and stars revolve around the earth. The sun rises and sets in different places but the earth seems to stand still. If the earth is spinning, then why don’t we feel wind? And for fifteen-hundred years, Christians, who held the scepter of truth, proclaimed the earth as the center of the universe. It wasn’t until Copernicus published his astrological work in the mid-sixteen century that people began the see things differently.

Why does science define a theory in a special way?

Science goes to great lengths to define things in specific ways. This is partly to be very clear about what you are explaining. When I worked in research, we defined exactly what strain of rats we used and where we purchased them. If needed, we could produce the lot number from their birth record. The layman might think that rats are rats, but the researcher knows this is not true. Science usually works from the specific and detailed outward. Once we have a glimpse of an answer with the specific, we expand our tests outward to see if the story will hold for the group. It often doesn’t.
There is legitimate confusion that rests in the collision between technical and colloquial language. In everyday terms, a theory is a best guess. “You wanna know my theory? His head’s too messed up with his divorce to maintain his batting average.” But in scientific terms, a theory has a specific meaning. It is an over-arching explanation that unifies a set of laws and observations.
Note that a theory is not a collection of facts. This misunderstanding is the source of any number of tabloid headlines. “Primitive tooth found in Kansas overturns evolution!” A theory is an overarching description from several disciplines that ties facts together. It can be tricky.
What About Other Theories?
Virtually all facts fall under some sort of unifying theory. Besides the Theory of Evolution, other examples include quantum theory, game theory, and the general theory of relativity. None of these theories seem to bother anyone which reinforces my idea that evolution is threatening primarily because it impacts religious and cultural beliefs about our world and ourselves.
Are there other options?
Brain in Vat Cartoon
There are other explanations for the diversity of life on earth. None are scientific. My favorite, indeed my favorite explanation for a multitude of things, is the brain in a vat. This position states that your entire life is a long series of neural inputs that make you believe you are experiencing something outside of yourself. It’s The Matrix.
Each religion has its own explanation, too. One Hebrew tradition is that G created all life within the six days of creation. G made and then Adam named all creation. Certain modern Christian groups argue strongly for a literal interpretation of this belief as both essential to their faith and as most consistent with observations of the world. Traditional Hinduism teaches that the universe is repeatedly created and destroyed and that we all exist in an eternal boom-bust cycle seeking enlightenment. Other religions including Voodoo, Santeria, and forms of animism typically mix modern religion, usually Catholicism, with local customs to create their own stories of Sun-gods and Sky-daughters.
Should these traditions be taught in the classroom? I vote with a firm Yes. They are fascinating subjects that tell us something about human beings and society. It’s important for an educated population to know the history of their people and of the world. It’s even more important as the world continues to shrink due to the Internet. Should these stories be taught in biology class? No. They are not scientific and fail all tests of scientific inquiry.

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Go here to read my post about the philosophical basis for the science of evolution.

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