We often hear Darwin lobbyists claim that evolution (meaning neo-Darwinian evolution) is “both theory and fact.” For example, Wikipedia (which is never shy about advocating specific points of view) has a page titled “Evolution as theory and fact” that cites various authorities on this, including Larry Moran’s Evolution is a Fact and a Theory, Stephen Jay Gould’s article “Evolution as Fact and Theory,” Richard Lenski’s article “Evolution: Fact and Theory,” and Theodosius Dobzhansky’s infamous paper Nothing in Biology Makes Sense Except in the Light of Evolution.
Now, Northern Arizona University philosopher Peter Kosso has blown the cover on the claim that evolution is “both theory and fact.” He does so in a short piece published by Springer Briefs in Philosophy, “A Summary of the Scientific Method” (Springer, 2011). In the paper, he challenges the typical definition of “theory” used by the Darwin lobby.
When attacking opponents, Darwin lobbyists typically define “theory” as “a well-substantiated explanation of some aspect of the natural world that can incorporate facts, laws, and tested hypotheses” (National Academy of Sciences, 1999) or “a comprehensive explanation of some aspect of nature that is supported by a vast body of evidence” (National Academy of Sciences, 2008). Using such definitions, saying the “theory of evolution” now necessarily implies an idea that is “well-substantiated” and “supported by a vast body of evidence.” Darwin lobbyists then scold those who say that “evolution is just a theory” as misunderstanding the definition of the term “theory” and also mock them for unwittingly implying that evolution is well-supported. But is that what “theory” really means?
Kosso observes that in practice, the term “theory” says little about the degree of certainty that characterizes an idea. As he notes “neither ‘theoretical’ nor ‘law’ is about being true or false, or about being well-tested or speculative.”
How does Kosso define theory? He writes that “all theories describe objects or events that are not directly observable. This is the core concept of theory. A theory describes aspects of nature that are beyond (or beneath) what we can observe, aspects that can be used to explain what we observe.” He continues:
Germs, atoms, caloric, curved spacetime, and elemental strings are all, to one degree or another, unobservable. That’s what makes them theoretical. But that doesn’t make them unreal.
Kosso goes on to explain that saying something is a “theory” doesn’t necessarily imply it is a “fact,” or even that it is well-supported by the evidence:
A theory is true if it describes unobservable things that really exist and describes them accurately. Otherwise it is false. This shows the mistake in contrasting “theory” and “fact.” A fact is an actual state of affairs in nature, and a theory, or any statement for that matter, is true if it matches fact. Some theories are true (atomic theory), some are false (caloric theory), and the scientific method is what directs us in deciding which are which.
Thus, Kosso has blown the cover on the Darwin lobby’s attempt to redefine theory to necessarily imply a concept which has strong evidential backing and is “well-tested” or “supported by a vast body of evidence.”
Kosso continues, stating: “To say of some idea, That’s a theory not a fact, is a confusion of categories, a comparison of apples and oranges.” While I agree with Kosso on this, it would stand to reason that it is also a confusion of categories to say “That’s a theory and a fact.” Thus, Kosso’s argument also could cut against Darwin proponents who say “Evolution is both theory and fact.”
Amending My Recommendations For Expressing Skepticism of Neo-Darwinian Evolution
A few years ago, I wrote a series where I explained why using the line that “evolution is a theory, but not a fact” is an ineffective way of expressing skepticism of neo-Darwinism. As I wrote:
I’ve long opposed using such a rhetorical line of “evolution is just a theory, not a fact” to oppose evolution because it gets you caught up in a semantic debate over the proper definition of fact and theory, and communicates very little about the most important component of this debate — the scientific evidence. … What follows is a slightly longer description of what one might say to communicate doubts about neo-Darwinism while avoiding semantic mistakes and communicating more than mere soundbyte arguments:
When evolution is defined as mere change over time within species, no one disputes that such evolution is a fact. But neo-Darwinian evolution — the great claim that unguided natural selection acting upon random mutations is the driving force that produced the complexity of life — has many scientific problems because such random and unguided processes do not build new complex biological features. According to the technical definitions of “theory,” “fact,” and “hypothesis,” such neo-Darwinian evolution is neither theory nor fact. It’s just a hypothesis.”
Today, I continue to very much stand by the position that the “evolution is a theory, not a fact” or “evolution is just a theory” lines are poor and ineffective means of expressing skepticism of neo-Darwinism. However, in light of Kosso’s definitions of “theory,” driven by no discernible agenda, I would like to amend myself.
What follows is an amended description of what one might say to communicate doubts about neo-Darwinism while avoiding semantic mistakes and communicating more than mere sound-byte arguments:
When evolution is defined as mere change over time within species, no one disputes that such evolution is a fact. But neo-Darwinian evolution — the great claim that unguided natural selection acting upon random mutations is the driving force that produced the complexity of life — has many scientific problems because such random and unguided processes do not build new complex biological features. Neo-Darwinian evolution is a theory that has been falsified by the evidence.
And that’s a fact.