We have often heard that evolution is a fact. As a matter of fact, some claim that it’s not even a theory since we know it to be true. But what do we actually know about evolution to be true? Before we consider the answer to that question, it’s important to understand some other facts about what is meant by the word evolution.
If we take evolution to simply mean “change over time”, I think it’s fair to say that it is a fact: things do change over time, and there is plenty of evidence to support that. However, if what we mean by evolution is what Darwin proposed, then I think we have good grounds for calling it, not a fact, but a belief.
The evolutionary biologist, Francisco Ayala, says that the word “evolution” can be used to mean at least three different things:
1. The process of change and diversification of living things over time.
2. Reconstruction of evolutionary history, showing how various lineages branched off from one another on the universal tree of life, which presupposes a single common ancestor for all life.
3. The mechanisms which account for evolutionary change, also known as Darwinism. This includes natural selection operating on random variations in living things in order to explain the adaptedness of organisms to their environment. Not only does this meaning also assume a single ancestor for all life, it goes a step further to explain how this evolutionary change is brought about.
Now evolution in the senses of (2) and (3) is not an established fact, despite what you hear being said in popular culture. It is only in the sense of (1) that evolution is a fact, but not even the most fundamental young earth creationist would have an issue with that, not to speak of others.
According to Ayala, “The second and third issues–seeking to ascertain evolutionary history as well as to explain how and why evolution takes place–are matters of active scientific investigation. Some conclusions are well-established. Many matters are less certain, others are conjectural, and still others . . . remain largely unknown” (Darwin and Intelligent Design). With respect to (2) Ayala emphasizes, “Unfortunately, there is a lot, lot, lot, to be discovered still. To reconstruct evolutionary history, we have to know how the mechanisms operate in detail, and we have only the vaguest idea of how they operate at the genetic level, how genetic change related to development and to function . . . I am implying that what would be discovered would be not only details, but some major principles” (Where Darwin Meets the Bible). As for (3), he cautions, “The mechanisms accounting for these changes are still undergoing investigation . . . The evolution of organisms is universally accepted by biological scientists, while the mechanisms of evolution are still actively investigated and are the subject of debate among scientists” (The Evolution of Life: An Overview).
It’s important to note that the adequacy of these mechanisms has sharply been challenged by some of the top evolutionary biologists. Lynn Margulis has even went as far as saying that “Darwinism is dead”. Ayala actually agreed with her! Over 500 scientists have become skeptical of Darwin’s theory, with some even questioning common decent.
So while evolution in a harmless sense can be called a fact, common decent and Darwinism, are not at all universal among scientists. Clearly, there are different ways the word evolution can be used. So when you hear it being used, it’s important to understand how it’s being used. If the user wants to assert that evolution is a fact, they need to refrain from using other words like “common decent, natural selection, and random mutation” along with it because that assumes Darwinism! Far from being a fact, evolution in the Darwinian sense is only a belief.