Five Criteria for Discerning the Best Explanation

To unearth some more tools for evaluating explanations, let’s revisit the scenario from Part 1 of this article:

Imagine you come home one day and find one of your windows broken. Shards of glass are laying both inside and outside the broken pane, but you don’t see any other foreign materials or markings near the window. What might have happened?

Among the many possible scenarios we could invent to try explaining the broken window, a few might include the following:

• A burglar smashed it.
• A baseball went through it.
• Someone inside the house broke it by accident.
• A UFO hit it.

When multiple explanations exist for a certain phenomenon—whether a broken window, an unusual fossil, or the existence of life on earth—how can we tell which explanation is best? If the explanations have met the minimum consistency requirements, we can evaluate those explanations further with five “criteria of adequacy.”1 These criteria can’t prove an explanation is true. After all, as we saw in Part 1, the best explanation is not necessarily the correct explanation. But these five criteria can help us determine which explanation is most likely to be true, given our current knowledge.

Criterion #1: Testability

To check if an explanation is testable, ask, “Does this explanation lead to falsifiable predictions?” In other words, are there any other phenomena you’d expect to observe if the explanation were true? For instance, if it were true that a burglar smashed the window, you might predict that valuables would be missing from your house. But if a baseball went through the window, you may expect to find a baseball in your living room. To test these predictions, you’d simply check for valuables’ absence or a baseball’s presence.

If you do end up observing the phenomena you expect, that doesn’t necessarily prove the explanation is true.2 Conversely, if you don’t observe the expected phenomena, that doesn’t necessarily prove the explanation is false.3 This is because there may be other reasons for the observations you uncover. For example, a baseball may be in your living room because a friend came over after sports practice. Or, your valuables may still be present because a burglar was forced to run away before seizing anything. However, if such possibilities are highly unlikely, you have good reason to (dis)believe the explanation.4

What about the UFO explanation? Unless you expect a UFO collision to leave extraterrestrial shrapnel, the idea that a UFO broke the window would be much harder to test. A lack of testability doesn’t automatically guarantee an explanation is false. But without more information, we also have no reason to believe the explanation is true.

Is Biblical Creation Testable?

My textbooks said supernatural explanations for events such as life’s origins do not yield testable predictions. And certainly, not all supernatural explanations are especially testable. For example, we couldn’t very well empirically test the explanation that an evil spirit broke the window.

We can, however, test many predictions that arise from a biblical worldview. For instance, we’d predict that a global flood would—as Ken Ham says—leave billions of dead things buried in rock layers laid down by water all over the earth. As another example, Dr. Nathaniel Jeanson’s book Replacing Darwin documents how biblical creation models predict multiple observations from genetics that are not consistent with evolutionary predictions.

Criterion #2: Fruitfulness

Fruitfulness5 is an explanation’s ability to predict previously unknown or unexplained phenomena. The more novel, successful predictions an explanation makes, the more fruitful the explanation is. For example, Dr. Russel Humphreys’ biblically based model for magnetic field decay not only matched known data but also accurately predicted magnetic field strengths for Uranus and Neptune before they were measured. Biblical models also make sense of otherwise hard-to-explain phenomena, including soft tissue in dinosaur fossils and carbon-14 in supposedly millions-to-billions of years old fossils and diamonds.

Criterion #3: Scope

Scope refers to the diversity and scale of observations that are consistent with an explanation. Take, for example, the following two explanations for the origins of rock layers:

• Explanation traditionally taught in textbooks: “Most layers accumulated gradually over millions of years.”
• Biblical explanation: “Most layers accumulated rapidly in the global flood.”

Many geologists no longer believe the traditionally taught explanation because it is inconsistent with so many observations regarding the rock layers. However, a biblical explanation not only is consistent with the rock layers themselves but also accounts for a plethora of other observations. As this article and other resources unpack, some of the many observations that the biblical view explains include:

• Marine fossils far above sea level
• Rapidly buried fossils and fossil graveyards around the world
• Sediments deposited over vast distances
• Ripple marks suggesting water consistently flowed northeast to southwest all across North and South America
• Global flood legends worldwide
• Zero indication of erosion between rock layers supposedly separated by millions of years
• Areas where many sediment layers bent without fracturing, suggesting they bent while still soft

By accounting for such a vast array of diverse observations, the biblical explanation for rock layers boasts impressive scope.

Criterion #4: Simplicity

The fewer assumptions an explanation contains, the simpler that explanation is. The simplest explanation is not always the right one; it’s just the one that—all else being equal—seems likeliest compared to more complicated explanations. (You may know this as Occam’s razor.) For instance, the explanation that a UFO broke the window is the least simple because it requires extra arbitrary assumptions about the existence of aliens.

Is Evolution the “Simpler” Explanation?

My critical thinking textbook claimed, “simplicity is an important advantage that the theory of evolution has over creationism . . . . Creationism must assume the existence of a Creator and the existence of unknown forces (supernatural forces used by the Creator). But evolution does not make either of these assumptions.”

No, it doesn’t. But any evolutionary view that assumes everything had a natural beginning must also assume that, among other things, a material universe can arise spontaneously, order can arise from chaos, life can arise from non-life, and information can arise from non-intelligence. These assumptions are inconsistent with observational science—and not to mention, with known laws of our observable universe.6 Such assumptions hardly make for a “simple explanation.”

Criterion #5: Conservatism

Conservatism corresponds to how well an explanation matches our prior knowledge of reality. For instance, the explanation that aliens broke the window is unsupported by observational science and Scripture. So, the UFO hypothesis scores low for conservatism. If you live next to a baseball diamond, however, the baseball theory would have higher conservatism. Similarly, biblically based models of how species diverge within kinds of living things match our prior observations that organisms reproduce “according to their kinds.”

The Ultimate Reason to Believe an Explanation

What if, as you’re weighing different explanations for the broken window, a trusted neighbour walks over and tells you that they saw a vandal smash the glass? The surest way to know what happened in the past is reliable testimony from someone who observed it. When it comes to origins, God’s Word provides that testimony from the only One who’s always existed, knows everything, does not make mistakes, and cannot lie.

In the end, then, a biblical worldview tends to generate models that satisfy every standard of a sound explanation. Biblical explanations fulfill the minimum requirement of internal and external consistency described in Part 1. They often score admirably for testability, fruitfulness, scope, simplicity, and conservatism. And they’re based in the ultimate foundation for a good explanation: infallible eyewitness testimony.

For more information:

Successful Predictions by Creation Scientists

Creationists’ Power to Predict

Must Science Exclude the Supernatural?

Creation science Q&A

“Sedimentary Layers Show Millions of Years of Geological Activity”