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Course 19 · Lesson 2.2

What the theory of evolution claims and what it does not

11 minute read

Lessons in this course

Course 19 outline

Module 1: The Secular Age: Humanism and Naturalism

  1. What secular, secularism and secularization mean
  2. Secular humanism: its claims and its moral vision
  3. Philosophical naturalism and its alternatives
  4. Christian responses to naturalism and humanism

Module 2: Science, Evolution and Faith

  1. Models of science and religion: conflict, independence, dialogue, integration
  2. What the theory of evolution claims and what it does not
  3. Christian positions on creation and evolution
  4. The history of the conflict story and its critics

Module 3: Criticism of the Bible

  1. The rise of historical and literary criticism
  2. What critics claim about authorship, sources and development
  3. Catholic, Orthodox and Protestant responses to criticism

Module 4: Truth, Relativism and Postmodernism

  1. What postmodernism is, and why the term is hard to define
  2. Truth, language and interpretation
  3. Moral relativism: descriptive, cultural and philosophical forms
  4. Christian responses to relativism and postmodern thought

Module 5: The Masters of Suspicion

  1. Marx on religion, ideology and economic life
  2. Nietzsche on Christianity, morality and the death of God
  3. Freud on religion as illusion
  4. The genetic fallacy, and when explaining the origin of a belief matters

Module 6: Power, Corruption and Morality

  1. Church, state and political power in history
  2. Institutional failure and abuse
  3. Critiques of Christian morality and how Christians reply
  4. Judging a faith by its failures: what follows and what does not

Module 7: Mind, Meaning and Nihilism

  1. Consciousness and the limits of materialism
  2. Meaning and purpose in secular and Christian thought
  3. Nihilism, despair and Christian hope

Module 8: Writing a Response

  1. Stating a challenge in its strongest form
  2. Building a structured response
  3. Conceding what is true in the critic’s case

All courses

Program / Course 19: Modern Challenges / Lesson 2.2

What you will learn

  • State the core claims of the modern theory of evolution in plain terms.
  • Distinguish common descent, natural selection and the broader worldview sometimes called evolutionism.
  • Describe the kinds of evidence scientists cite, and the questions that remain open inside the science.
  • Identify claims that are often attached to evolution but are philosophical, not scientific.

The big idea

The theory of evolution says that living things share common ancestors and have changed over a very long time, and that natural processes such as natural selection, genetic variation and drift drive much of the change. It is the central framework of modern biology, and the great majority of working biologists accept it. It does not say how life first began, and it does not say whether God exists or whether human life has a purpose. When people claim that it does, they are adding a philosophy to the science.

Key terms

Evolution
In biology, change in the inherited features of populations over generations.
Common descent
The claim that all living things share ancestors, so that species are related by branching descent.
Natural selection
The process by which inherited traits that help organisms survive and reproduce become more common in a population.
Mutation
A change in an organism’s genetic material, one source of new variation.
Abiogenesis
The origin of life from non-living matter. It is a separate research question from evolution, and it is not settled.
Fossil record
The preserved remains and traces of past life, found in layers of rock that can be dated.
Evolutionism
A word used for a worldview that extends evolution into a general philosophy of life and denies purpose. It is not part of the scientific theory.
Macroevolution and microevolution
Terms for large-scale change (new species or groups) and small-scale change within a population. Biologists see them as differences of degree, and some creationists see a difference of kind.

Background

Charles Darwin published On the Origin of Species in 1859. He argued that species were not separately created but descended from common ancestors, and that natural selection was a main cause of change. Earlier thinkers had suggested that species change, and Alfred Russel Wallace reached similar ideas independently. Darwin did not know the mechanism of heredity. In the early twentieth century, Mendel’s work on genetics was combined with selection in what is called the modern synthesis. After Watson and Crick described the structure of DNA in 1953, molecular biology has added a great body of evidence.

Today evolution is a large research field with active internal debate over, for example, the relative importance of selection and drift, the pace of change, the role of development, and the origin of the first cells. These debates are about how evolution works, and not about whether species are related. A student should not confuse the existence of arguments inside science with doubt about the framework.

Step-by-step explanation

Step 1: The core claims

The theory makes three main claims. First, the earth is very old, about four and a half billion years by current measurement, and life has existed on it for most of that time. Second, living things are related through common descent. Third, change comes through natural processes, of which natural selection is central. The details of each are matters of research.

The theory is also a statement about humans. Biologists conclude that human beings are related to other primates and share ancestors with them. This is the claim that touches Christian teaching most closely and is taken up in the next lesson.

Step 2: The kinds of evidence

Scientists cite several lines. The fossil record shows a succession of forms through rock layers, including transitional forms such as early whales with legs and Tiktaalik, a fish with limb-like fins. Comparative anatomy shows shared structures in different animals. Genetics shows that the DNA of related species is more similar, and that humans and chimpanzees share a very high proportion of their sequence. Observed change in populations, such as bacteria that gain resistance to drugs, shows selection at work.

Critics of evolution raise questions, for example about the origin of new information, of complex structures, or of the first cell. Biologists reply that many of these have research answers and some are open questions. The Intelligent Design movement, associated with Michael Behe and William Dembski, argues that some features show signs of design. Most biologists reject its claims as unsupported, and some philosophers consider design arguments legitimate in principle.

Step 3: What the theory does not claim

The theory does not explain the origin of life. It does not explain the origin of the universe. It does not say that evolution is random in every respect, since selection is not random, though mutation is undirected in the sense that it does not aim at what the organism needs. It does not say that humans are not special, or that morality is an illusion, or that life has no purpose. These are philosophical or theological conclusions.

A scientist may argue for such conclusions, as Richard Dawkins does, but he then argues as a philosopher. Other scientists who accept the same biology, such as Francis Collins or Ken Miller, hold that evolution is compatible with faith. The fact that both groups read the same science supports the point.

Step 4: Chance, purpose and direction

One worry is the word chance. In biology it means that mutations are not caused to meet a need. That is a statement about causal structure. It is not a claim that nothing guides the process. Classical theology holds that God works through secondary causes, which are the ordinary causes in nature, and that events which look accidental to human observers are not outside his care (Proverbs 16:33). Others, such as many in the Intelligent Design movement, deny that this suffices.

Some scientists, such as the paleontologist Simon Conway Morris, argue that evolution tends to converge on similar solutions, and that this supports the view that the outcome was not arbitrary. Others, like Stephen Jay Gould, held that if the tape of life were replayed, humans would not appear. This question is open in science and philosophy.

  1. Is this claim about biological facts, or about the meaning of life?
  2. Does the speaker use evolution to mean common descent, natural selection or a worldview?
  3. What evidence supports the claim, and is it disputed within biology?
  4. Does the speaker confuse the origin of life with evolution?
  5. What does chance mean in this sentence?
  6. Would a biologist who is a Christian say the same?

Examples

Bacterial resistance

A hospital finds that an antibiotic no longer kills a common bacterium. A few bacteria in the population carried a variation that let them survive, and they multiplied. This is natural selection observed within a lifetime. (A constructed, simplified example.)

Science and worldview mixed

A lecturer says that since species evolved by natural selection, human life has no purpose. The first part is biology. The second is a philosophical conclusion for which the biology gives no proof. (A constructed example.)

A scientist who is a believer

A geneticist spends her career comparing the genomes of related species. She goes to Mass on Sunday and sees no conflict, believing that God works through the processes she studies. A colleague, equally expert, thinks the same data show that religion is false. (A constructed example.)

Different perspectives

Scientific consensus

The overwhelming majority of biologists accept common descent and natural selection as established. Scientific organizations around the world hold this view. Internal debates concern mechanisms and details, such as the roles of drift and development, and the origin of life remains unsolved.

Catholic

Pope Pius XII in the 1950 encyclical Humani Generis allowed that evolution may be studied as a hypothesis, while insisting that souls are directly created by God. John Paul II in 1996 said that evolution is more than a hypothesis, again affirming the special creation of the soul. The Church has not defined a position on the biological details.

Orthodox

There is no official Orthodox teaching on evolution. Many Orthodox scientists and theologians accept it, while others, particularly the monastic writer Seraphim Rose, argued against it. Orthodox writers generally stress that God is Creator of all, and some caution against reading Genesis as a scientific text.

Protestant

Protestants hold a wide range. Many evangelical scientists, such as Collins, accept evolution as God’s method. Some conservative Protestant churches teach young earth creationism. Benjamin Warfield, a leading nineteenth century Reformed theologian, was open to evolution as a mechanism within God’s providence while holding the full authority of Scripture.

Why it matters

A Christian who rejects what biology claims will be dismissed. A Christian who accepts more than biology claims will give up beliefs the science never touched. The aim of this lesson is to learn exactly where the science stops, so that disagreements can be placed where they belong.

Common misunderstandings

Misunderstanding: Evolution says that life came from nothing by chance.

Correction: Evolution addresses how populations change after life exists. The origin of life is a separate and open question, and selection is not random.

Misunderstanding: Evolution is just a theory, meaning a guess.

Correction: In science a theory is a broad, well-tested explanation. It is not a hunch. Evolution is a theory in the same sense as germ theory or the theory of gravity.

Misunderstanding: Accepting evolution means rejecting God.

Correction: Many Christians accept evolution. Whether it conflicts with faith depends on how Genesis is read and on whether evolution is joined to a philosophy that denies purpose.

Misunderstanding: Scientists are hiding that evolution is in crisis.

Correction: Biologists debate mechanisms openly. Disagreement about mechanisms is not doubt about common descent.

Knowledge check

State the three core claims of evolutionary theory.

The earth is very old, about four and a half billion years, and life has existed for most of that time. Living things are related by common descent. And change in populations comes through natural processes, of which natural selection is central. Genetic mutation supplies variation, and drift and other factors also contribute.

What does the theory of evolution not explain?

It does not explain the origin of the first life, which is a separate research problem called abiogenesis, nor the origin of the universe. It also does not decide whether God exists or whether life has purpose. Those are philosophical and religious questions that scientists and others answer in different ways.

What does chance mean in biology?

It usually means that mutations occur without regard to what the organism needs. It is a claim about causes, not about whether God is involved. Classical Christian teaching holds that God works through secondary causes and that events that look accidental to human observers are within his providence. Some Christians disagree and think this reading fails.

Why do believers and unbelievers draw different conclusions from the same biology?

Because the conclusion about God or purpose is philosophical and depends on further beliefs. A biologist can accept common descent and selection and then hold that nature is all there is, or hold that God created through these means. The science does not decide between them, which is why informed scientists are found on both sides.

Think it through

  1. What did you first learn about evolution, and from whom?
  2. Which common claim about evolution have you now seen to be a philosophical addition?
  3. Does the idea of undirected mutation trouble you? Why or why not?
  4. How can a Christian disagree with a scientific claim without misrepresenting it?

Independent assignment

Separate the science from the philosophy

In your notebook, take a passage from a popular book, film or article about evolution (either for or against it). Underline every sentence that makes a factual claim about biology, and mark in a different way each that makes a philosophical or religious claim. Write 300 to 500 words on what you found. Do not post it.

Further study