Commenting on the philosophical implications of quantum mechanics, physicist Richard Feynman said, “It is not true that we can pursue science completely by using only those concepts which are directly subject to experiment….The basis of a science is its ability to predict.” (The Feynman Lectures on Physics, Vol. III, pp. 2-9)

We can appreciate this statement by contrasting it with the popular view, where science is a matter of measuring and experimenting with observable reality. Feynman points out that with the advent of quantum mechanics, the scientific reality of nature is no longer directly observable, even in principle. Probabilistic predictions are actually all that quantum theory allows. 

However, while predictive accuracy is a necessary attribute of a scientific theory, it is by no means a sufficient indicator of the theory’s truth. A theory may predict well enough, but we need to ascertain if its assumptions are true. In other words, do the assumptions of the theory correspond to reality? The concept of reality means an accurate description of nature that is consistent with experimental observations and established laws of physics. Such tests can tell us if an idea counts as a true scientific theory.

Let’s illustrate these requirements by considering several cases from the history of science — including Darwinian theory. But first, let us look further back to attempts to develop a theory that explained the motions of the celestial sphere — the astronomical realm thought to contain the stars and planets visible from Earth. 

The Geocentric Model

Readers will be familiar with the geocentric model of the solar system, most often associated with Ptolemy (second century CE). This model, embellished with planetary epicycles, gave reasonable predictions of the trajectories of the five visible planets, including their periodic episodes of retrograde motion. It also comported with the prevailing Aristotelean philosophy of the cosmos and agreed with everyday observations, in which all heavenly bodies appear to revolve around a stationary Earth. Nonetheless, the geocentric model was completely wrong.

Clues supporting the correct heliocentric model remained below the level of observational resolution until the advent of the telescope. 

Galileo was the first to use a crude telescope to obtain observational data that proved inconsistent with the geocentric model. His observations showed sunspots, which disappointed those who held to celestial perfection….Galileo also detected a full set of phases of the planet Venus, which was inconsistent with geocentricism. In sum, Galileo’s more accurate observations showed that this long-standing theory of how the solar system worked was incompatible with several aspects of physical reality. 

Canceled Science, p. 178

The heliocentric model, first published by Copernicus in 1543 (21 years before Galileo’s birth), although conceptually simpler and cleaner than the Ptolemaic model, initially failed to make better predictions. That was because Copernicus assumed perfect circles for the planetary orbits. In the early 1600s, Kepler analyzed detailed naked-eye observations of the planets to deduce the correct elliptical shape of their orbits around the sun, allowing for more accurate predictions. 

The point is that successful predictions of a theory do not prove its correctness. With technological developments in observational astronomy, evidence unequivocally demonstrated the foundational errors in the assumptions of the geocentric model. Ptolemy’s Earth-centered model is now taught only as an interesting phase in the history of astronomy. 

Spontaneous Generation

Another example of a now-discarded theory is that of spontaneous generation, a hypothetical process of living organisms developing from nonliving matter. The theory made accurate predictions, such as “maggots will appear in rotting meat,” but Pasteur’s experiments proved that the underlying assumption of the theory was false. We might ponder the significance of the timing of this example. Pasteur’s experiments, disproving the ancient belief in the spontaneous generation of life, coincided with the publication of Darwin’s On the Origin of Species in 1859.

Darwinian evolution as a theory of the development of life on Earth makes predictions that overlap with various lines of observational evidence, such as shared genetic and morphological traits among numerous species, both living and extinct. Given some predictive successes, along with observations of the mechanism of natural selection, extended assumptions of the theory have been presumed true. However, many shortcomings remain, both with the predictions and assumptions of Darwinian evolution. In a classic article, Casey Luskin details numerous failed predictions of Darwinism.

In Darwin’s day, the deep and interconnected functional biocomplexity of every living cell lay beneath the observational resolution available to science. Even so, as Robert Shedinger remarks in Darwin’s Bluff, Darwin “base[d] his continued confidence in his theory on the grounds that it, ‘explains so many facts.’” However, Shedinger adds, as we have already discussed, “this does not prove that a particular theory is correct.” (p. 57)

In Need of Restraint

The Bohr model of the hydrogen atom yielded a stunningly precise prediction of the wavelengths of the spectral lines of hydrogen. Yet a closer look involving quantum theory showed that fundamental assumptions of the Bohr model were incorrect. It is very tempting, especially for the inventor of a theory, to believe that the theory must be correct if it produces predictions that overlap with reality. But utmost restraint needs to be employed not to conflate successful predictions of a theory with the truth of the theory’s assumptions.

An assumption of evolution is that natural processes suffice to have produced the vast information required for cellular reproduction and function. This represents an increase in information by natural processes over the passage of time, in disagreement with established laws of theoretical physics.

Meanwhile it has turned out that the predictions of the theory of Darwinian evolution have an overall accuracy that is arguably worse than that of the long-entrenched geocentric theory of the solar system. With ongoing scientific advances, the assumptions of Darwinism, both those on which it is based, and other assumptions extrapolated from the theory’s presumptive truth, have come under increasingly critical scrutiny. Darwin’s original theory and modern syntheses of it thus fail to satisfy the requirements of a valid scientific theory: Several of its predictions don’t adequately match reality, while its fundamental assumption, of life in all its forms arising without a designer, conflicts with established laws of physics. 

The influence of evolutionary thought arises as an outgrowth of uncritical acceptance of its assumptions, but the theory deflates like a punctured balloon when those assumptions are exposed as falsehoods. Rather than its continuing to dominate scientific thought, the curtain has been pulled back on Darwinian evolution. As evidence continues to accumulate contrary to the predictions and assumptions of evolution, its place on the shelf of discarded theories in the history of science is already being prepared.