Providing a definition of “evolution” is tricky because the word is used in different ways. First we need to distinguish between the broader worldview some associate with evolution and the scientific theory of evolution.
Evolution as worldview
Some people consider evolution to be equivalent to atheism, thinking it replaces God or otherwise rules out God’s involvement in the development of life. But that is a philosophical or worldview position (sometimes called “evolutionism” or simply “naturalism”), not a strictly scientific position.Read more on worldviews and evolutionism
Worldviews can certainly affect how we interpret scientific evidence, and scientists must make assumptions (e.g., the natural world is regular and intelligible) and rely on extra-scientific values (e.g., simpler theories are better than more complex theories with the same explanatory power). But the science of evolution does not depend on assumptions and values that are contrary to Christian theism.
An example of evolutionism is this quote by George Gaylord Simpson:
Man is the result of a purposeless and materialistic process that did not have him in mind. He was not planned. He is a state of matter, a form of life, a sort of animal, and a species of the Order Primates, akin nearly or remotely to all of life and indeed to all that is material (The Meaning of Evolution, p. 344).
This is not a scientific statement. It is an expression of a more comprehensive worldview that draws conclusions far beyond what could ever be shown by science.SEE ALSO:
At BioLogos, we are against evolutionism and instead hold to the worldview of Christian theism. We call our position on origins “Evolutionary Creation.” That is to say, we believe God is the Creator and also accept that evolution is the best scientific description for how life has developed. This is similar to saying we believe God provides for the growth and development of plants while we also accept that the theory of photosynthesis is the best scientific explanation for that process.Read more on evolutionary creation
What We Believe gives a detailed list of our beliefs on science and Christianity.SEE ALSO:
Evolution as a scientific theory
In non-scientific contexts, “theory” usually means something like a guess (e.g., I have a theory about…). But in its scientific sense, a theory is a tested and well-confirmed explanation for a set of observations. The observations explained by the theory of evolution come primarily from the fossil record, comparative morphology, biogeography, and now most importantly, genetics. Evolution does not attempt to give a scientific explanation for the origin of life, but only for the development and diversification of lifeforms after the first life began.Read more on the evidences for evolution
Fossil record: see our Common Question, “What does the fossil record show?”
Comparative morphology: comparing the body plans of plants and animals
Biogeography: the distribution of species around the planet is consistent with a pattern of common ancestry, not distribution after Noah’s flood.
Genetics: see our Common Question, “What is the genetic evidence for human evolution?”
The theory of evolution states that all the lifeforms on earth share a common ancestor as a result of variation and selection over a very long time (currently thought to be around 4 billion years). Variation means that offspring are not exact replicas of their parents, and selection occurs when only some of those offspring go on to produce more of their own offspring. Common ancestry does not mean the species we find today have evolved from each other—dogs did not evolve from cats, and humans did not evolve from chimpanzees. Instead, if you go back far enough in the ancestral tree of any two organisms, common ancestry predicts that you’ll come to a “grandparent” of which both current organisms are descendants. For humans and our closest relatives the chimpanzees, you have to go back around 300,000 generations to find that common ancestor (that would be your 299,998th-great grandparent!). What did that process look like?
That ancient population (which was neither human nor chimpanzee) split into two groups, and these groups were reproductively isolated—that is, the members of each group only mated with other members of the their own group. Then over the many generations of offspring, different variations were preserved in each group. Eventually the characteristics of each group were different enough for scientists to recognize them as different species. The theory of evolution claims that a similar story could be told for the ancestral lineage of any two species that have ever lived.Read more on what a species is
What is a species? We easily recognize the difference between very different species, and this contributed to the pre-Darwinian view that species are static. But evolution happens gradually, and this means there are lots of gray areas where it is not clear whether certain individuals belong to the same species or to different species. This problem occurs both for presently existing species and as we look back at the ancestors of a species. Experts are informally referred to as “lumpers” or “splitters” depending on whether they tend to put slightly different organisms into the same species or divide them into multiple species.
Debates about evolution
There is very little debate in the scientific community about this broad characterization of evolution (anyone who claims otherwise is either uninformed or deliberately trying to mislead). The observational evidence explained by common ancestry is overwhelming. Of course new data causes scientists to adjust some of the specifics (like how long ago species diverged, or which species are most closely related), but this core view is overwhelmingly supported and agreed upon by the vast majority of scientists in the field.Read more on survey data of scientists
The Pew Research Center has done extensive polls of the American public and scientists about evolution. They found that 99% of scientists in biological or medical fields agree with the statement that humans have evolved over time. Our blog posts on these topics have all the relevant citations:SEE ALSO:
But that is not to say there are no debates and controversies about evolution among those who accept this core view of the theory. Evolutionary scientists debate the extent to which the variation element is explained by random genetic mutations, and how important other selection mechanisms are beyond reproductive fitness. Scientists have different views on topics like how gradual evolutionary change is and on the details of how natural selection works. And as we’ve already seen, there are significant differences of opinion about how to interpret various aspects of evolution with respect to worldviews, such as whether there is overall direction to evolution, and what the significance of evolution is for theology.Read more on controversies in evolution
At BioLogos we believe the best contemporary science is consistent with Christian theology. Find more information on evolution and the BioLogos perspective on origins in the other resources on this page or by searching on particular terms in our search box.Read more on evolution and the BioLogos perspective
Other resources on our website related to this topic can be found in the tiles under "Further Reading." Specifically, consider these series:
BioLogos Basics is a series of short animated videos highlighting the central themes of BioLogos.
Dennis Venema has written a wide-ranging series of blog posts for non-specialists on the science of evolution called Evolution Basics.
Ted Davis explores the various approaches Christians have taken to understanding how the science of origins relates to their their faith in his blog series Science and the Bible.
Some excellent evolution resources on other websites:
Stated Clearly videos This is a collection of animated videos (ranging from 5-11 minutes) describing the science of evolution.
UC Berkeley has put together a large number of introductory resources at its Understanding Evolution project.
The Howard Hughes Medical Institute has produced a number of high quality videos on evolution.
(Video #6 in the BioLogos Basics video series.) We often hear critics of evolution saying things like, “A dog could have never evolved from a cat” or “If humans... Read More >
(Video #7 in the BioLogos Basics video series.) In the previous video we looked at microevolution—small changes in a population on relatively short timescales. Most critics... Read More >
Opponents of evolution sometimes claim it is a theory in crisis. This is misleading at best. Read More >
The affirmation of genuine chance and randomness in the universe does not rob the universe of meaning and purpose. Read More >
Perhaps it’s a good idea for all of us to simply stand back in amazement while God does God’s work in God’s time through God’s process. Read More >
One of the difficulties people have with coming to accept the science of evolution is that they have absorbed incorrect or only partially correct information. Read More >
Considering evolutionary creation has important benefits for Christians both in our relationship with God and in our relationships with other people, believers and non-believers. Read More >
Written by BioLogos Fellow of Biology Dennis Venema, this series of posts is intended as a basic introduction to the science of evolution for non-specialists. Read More >
This ongoing series written by historian Ted Davis begins with a brief synopsis of his personal background, and then goes on to reveal his passion for debunking “the now-common ... Read More >
Page updated 29 April 2016