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Scientific Truth
By K. D. Bomben
Posted on: 4/23/2002
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What do scientists consider to be the "truth," how do they go about finding it, and just what is a "theory," anyway?
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And ye shall know the truth and the truth shall make you free.
— John 8:32 (KJV)
We all seek the truth, yet pursue it differently. Are humans allowed to search for the truth? According to the above quote from The Holy Bible, Jesus expects us to. But how do we search for truth? And how will we recognize it if and when we find it?
With so many possibilities, some theorists argue that truth itself is relative. Since everybody has an opinion, reality is subjective to individual perceptions. But for now, I’ll only address the scientific method and explain the difference between facts, hypotheses, theories, and laws. I also want to describe how knowledge itself evolves.
The scientific method is observation. Observations are plain facts. We observe, for example, that fire gives off heat and light. Webster defines a fact as “the state of things as they are; reality; actuality; truth.” Before we search for the larger truth, we must first accumulate small truths. Science grows by gathering singular, simple facts.
Soon, observations lead to questions. Suppose you watch an ant scurry over your kitchen table. You might ask, “Where did it come from?” and “What’s it doing here?” and finally, “Is that the only ant in my kitchen?” If you’re imaginative, you might assume that the ant is looking for food since it’s on your kitchen table. From here, your guess advanced your observation to a new stage — you’ve just formed a hypothesis.
Webster defines a hypothesis as “an unproved proposition tentatively accepted to explain certain facts or to provide a basis for further investigation.” Whenever you suggest an explanation for an unanswered question, you’ve taken part in the scientific method. Science always tries to explain why things happen, and proposes new hypotheses to accomplish that.
But how do we know if a hypothesis is true? In his Lectures on Physics, physicist Richard Feynman says, “The principle of science, the definition, almost, is the following: The test of all knowledge is experiment. Experiment is the sole judge of scientific Truth.”
For example, you can test your hungry ant hypothesis. Put some food in the ant’s path and watch what happens. If the ant stops and eats your food, your hypothesis looks promising. If it ignores the crumb, your hypothesis falters. But some experiments produce unexpected results. If the ant picks up the crumb and carries it off the table, what does that mean?
Could there be another hypothesis to explain why the ant didn’t eat the food? Should you reject your original hypothesis? Somehow, you must revise your original explanation to address your experimental results.
Remember “Cold Fusion?” That hypothesis tried to explain how an unexpected amount of heat followed a chemical reaction. Other chemists tried to duplicate that experiment, but nobody could duplicate the same results. Scientists then offered a new hypothesis to explain what went wrong with the original experiment.
When two hypotheses contradict one another, at least one of them is wrong. Indeed, the entire universe does not contradict itself. Scientists must reason, or use the process of elimination, to decide which of two or more scientific experiments best explains an observation. In other words, your hypothesis must fit all the facts. Since nobody else could reproduce the original cold fusion results, including the scientists who first reported them, the (proposed) theory of cold fusion turned out to be wrong.
Hypotheses that survive experimental scrutiny are subjected to more rigorous tests. The original idea is examined, twisted, dissected, criticized, and re-tested. If any test refutes a proposed hypothesis, that hypothesis must be discarded or modified to account for the new facts.
As evidence is gathered, as facts are compiled, as experiments are undertaken, the working hypothesis gains support. Little by little, a hypothesis becomes a theory. The scientific method demands that, when new evidence comes to light, the theory must change to accommodate that new evidence.
Consider gravity, for example. Sir Isaac Newton first hypothesized a law for gravitational attraction over three hundred years ago, and it withstood all challenges until we discovered that the speed of light is a constant. Suddenly, Newton’s theories didn’t reconcile all the known facts. Albert Einstein modified the theory (by now called the law) of gravity to explain all these new observations.
But Newton’s Laws of Gravitation are still relevant. Einstein only added a refinement to a realm (known as Relativity) that’s rarely observed in the familiar world. Einstein didn’t throw away three hundred years of observation and testing. (Don’t forget that any new theory must accommodate the old facts, too.) Instead, new knowledge is built on top of previous knowledge.
Einstein only tailored Newton’s Laws to fit the new facts. The old facts are still functional, and Relativity barely altered Newton’s findings.
This is where many people get flustered. How do you distinguish between a theory and law? Actually, there are two related definitions of “theory.” Most people assume a “theory” is something that’s a “mere hypothesis, conjecture or guess.” But in science, it specifically means “a formulation of apparent relationships or underlying principles of certain observed phenomena which have been verified to some degree.”
Indeed, the distinction is important enough that Webster devotes no less than ten lines to distinguish between these words with the following (here, abbreviated) notes:- Hypothesis — An inadequacy of evidence in support of an explanation.
- Theory — Considerable evidence in support of a formulated general principal (as in the theory of evolution).
- Law — Implies an exact formulation of the principle (as in the law of the conservation of energy).
In science, a theory carries a great deal of weight. Theories are backed by an incredible number of facts. As Webster implies, to dismiss evolution as “only a theory” is to grossly abuse the language. That’s like claiming Thomas Jefferson was “only a farmer.”
Stated simply, this is how the scientific method progresses:- Observations lead to questions
- Questions lead to tentative answers
- Answers are tested in a laboratory, in the classroom, or in the field
- Tests lead to modifications, and yet more tests
- Modifications ultimately lead to theories
- Theories lead to laws.
The law of gravity and the theory of evolution, for example, both lead to the Truth. Newton and Darwin’s ideas have both been refined and tested for more than 150 years in every laboratory around the world. Science demands that all observations be accounted for. Any new theory must build upon existing data. Newton’s formulas and Darwin’s vigilant observations still demand a consistent explanation.
By searching for truth, we can understand how the world works. We can then learn how to change the way the world works, and discover how our observations, in turn, alter that world.
By starting with facts or “little truths,” we build a self-consistent representation of the universe that we’ve always observed. The more we learn about our world, the more insight we gain about ourselves. We can answer questions today that our parents weren’t aware of. Hopefully, our children will build on that knowledge and, eventually, expose larger truths. Truth is ultimately found through a slow, incremental, step-by-step process of elimination — not divine revelation.
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