Evolution

When people talk about evolution there seems to be a lot of confusion caused by people using words in different ways. So let's start with a discussion about definitions.

Words often have two meanings: one meaning when used in a specific scientific discipline, and another meaning when used by the general public. When the word is used in the general public differently it is called the "vernacular".

Vernacular

Being or characteristic of or appropriate to everyday language; "common parlance"; "a vernacular term"; "vernacular speakers"; "the vulgar tongue of the masses"; "the technical and vulgar names for an animal species"

Now let's look at some words in evolution.

Evolution

When lay people use the word evolution they often mean:

1) The process of developing
2) a process in which something passes by degrees to a more advanced or mature stage

People speak about the evolution of an idea or the evolution of technology for instance. They often mean to infer that something has progressed to a higher level or improved some way. They also imply that the improvement was intentional. "The evolution of Greek civilization" is an example. Sometimes they mean that something has progressed from a simple, crude form to something more sophisticated and complex. "The evolution of the computer" for example.

However, in biology the word evolution rarely means any of these things. It is much more specifically defined and has two possible meanings:

1) A change in allele frequency in a population
2) Descent with modification from common ancestors, resulting in diversification/speciation

What does this mean in plain English? Organisms change over time. That is all, nothing more, nothing less. Evolution states only that life changes. It does not address how life began. That is abiogenesis. It does not say that life improved. Evolution is not planned. Nor does it say that the life forms we have now are "better". They are simply more adapted to the environment in which they find themselves. Nor does Evolution "think". It does not look about and say, "we could use one of these kinds of animals". New species simply happen, as a result of genetic mutations. They either survive or they don't.

However, neither are the very comlex life forms we see today the result of a single "fluke". They are the result of years and years of culling. Unsuccessful mutations died. 99% of all life forms that ever existed on this planet are now extinct. The ones which have survived are the result of a tremendous culling process that has lasted for billions of years.

How do organisms change? By genetic mutations.

Mutation

An error in copying the DNA.

It is important to note that not all mutations are bad. Most are benign. Some are fatal. Some are beneficial. How can a mutation be beneficial? Please see Mutations for a more in depth discussion.

What do I mean when I say a mutation is benign or fatal? A mutation is benign if it does not prevent the organism from reproducing and passing along the mutated gene. A mutation is fatal if the organism dies before being able to reproduce and therefore pass on the mutated gene. A mutation is beneficial if it provides the organism with an advantage when it comes to reproduction.

Speciation

Evolutionists often talk about speciation. Speciation is defined as:

The evolutionary formation of new biological species, usually by the division of a single species into two or more genetically distinct ones.

Hypothesis vs. Theory vs. Law

When a scientist wishes to explain some feature or phenomenon of the natural world, he makes an educated guess about its cause. This initial speculation, in scientific terms, is a hypothesis. Hypotheses eventually graduate to the status of theory if and only if enough evidence is found to support them.60

Hypothesis

A tentative explanation for an observation, phenomenon, or scientific problem that can be tested by further investigation.

Theory
In science the word theory means:

A set of statements or principles devised to explain a group of facts or phenomena, especially one that has been repeatedly tested or is widely accepted and can be used to make predictions about natural phenomena.

However, in the vernacular it means:

An assumption based on limited information or knowledge; a conjecture.

A scientific theory is not a "guess". It is an explanation of observed facts. A scientific theory must have predictive value, must be internally consistent, must be falsifiable, and must explain at least those phenomena explained by the currently dominant theory (Kirby, 2003).

There is a misconception amongst laymen that if enough evidence is found a theory becomes a law. This is simply not the case. A theory is either sound or unsound. There is no system where a theory gets promoted to fact or law within science. A theory is determined to be sound if it withstands the scrutiny of repeated experiments. Nowhere in history has a theory been raised in status to "law". 61

Law

In science, a law is a (usually mathematical) description of some feature of the natural world. A theory is an explanation of that feature. In other words, laws say what happens, while theories explain why it happens. The law of gravity states that two objects attract each other with a force proportional to the product of their masses and inversely proportional to the square of the distance between them. It says what happens, but not why; it does not explain what gravity is or how it works. The theory of gravity explains why such an attraction exists.60

A statement describing a relationship observed to be invariable between or among phenomena for all cases in which the specified conditions are met.
A scientific law can be reduced to math. A theory is equally esteemed but is too complicated to reduce to math.

For instance the law of gravity is:

F = G Ma Mb / r2

However, the theory of gravity is far to complex to present in this limited space.

Thus the concept that most of us think of as the "Law of Gravity" is more technically known as the "Theory of Gravitation"; similarly, we could talk colloquially of the "Law of Evolution" (The record, 2003).

Biologists know that evolution occurred. However, they are reluctant to imply, by the use of the word "law," that they know exactly how it occurred. And there lies room for debate. Whether evolution happens is not debatable. It is a fact.

Fact

There seems to be a lot of confusion about the meaning of the word "fact" in evolution. In science there is no such thing as absolute certainty. However, there is data which we know to be true. This is what constitutes "fact" in science. In science a fact is defined as:

Confirmed to such a degree that it would be perverse to withhold provisional consent.

In other words, a fact is something that is so highly probable that it would be silly not to accept it (Evolution is a fact, 2003).

There is also a great deal of confusion about theories and facts.

Theory vs. Fact

"...facts and theories are different things, not rungs in a hierarchy of increasing certainty. Facts are the world's data. Theories are structures of ideas that explain and interpret facts. Facts don't go away when scientists debate rival theories to explain them. Einstein's theory of gravitation replaced Newton's in this century, but apples didn't suspend themselves in midair, pending the outcome. And humans evolved from ape-like ancestors whether they did so by Darwin's proposed mechanism or by some other yet to be discovered" (Evolution is a fact, 2003).

In science, a theory is a rigorously tested statement. A scientific theory stands until proven wrong -- it is never proven correct. Why? Science never closes the door on future knowledge. Science never says: "We know all there is to know". It always allows that better technology and future knowledge may disprove current information. Scientists make no claim for perpetual truth. Science also allows that new information resulting from better technology may add to or change the theory.

Evolutionists have been very clear about this distinction of fact and theory from the very beginning, if only because we have always acknowledged how far we are from completely understanding the mechanisms (theory) by which evolution (fact) occurred. Darwin continually emphasized the difference between his two great and separate accomplishments: establishing the fact of evolution, and proposing a theory--natural selection--to explain the mechanism of evolution.
- Stephen J. Gould, " Evolution as Fact and Theory"; Discover, May 1981

It is a fact that all living forms come from previous living forms. Therefore, all present forms of life arose from ancestral forms that were different. Anti-evolutionists often oppose both the fact of evolution and theories of mechanisms. This is erroneous.

Evolution is a theory and a fact.

Biological evolution is defined as being any change in allele frequences in a population over time.

The fact of evolution is that this has been observed.

For a well-known example, black moths that became more prevalent in England after the Industrial Revolution and the soot that followed as camouflage. Because the frequency of genes for black color has gone up in the population, evolution has taken place. Speciation has also been observed in various experiments. For example, breeding of fruit flies have led to populations that cannot mate together, thereby bringing about two separate species. That evolution happens is an indisputable fact (Kirby, 2003).

The theory of evolution seeks to explain how this occurs. It makes predictions about what we can expect to find if the theory is correct. It also identifies elements that, if found, would disprove the theory.

Arguing Against Evolution

The theory of evolution is an explanation of observed facts. If you are going to argue against evolution you have to address those facts and provide a better explanation for them than evolution.

What evolution has is what any good scientific claim has--evidence, and lots of it. Evolution is supported by a wide range of observations throughout the fields of genetics, anatomy, ecology, animal behavior, paleontology, and others. If you wish to challenge the theory of evolution, you must address that evidence. You must show that the evidence is either wrong or irrelevant or that it fits another theory better. Of course, to do this, you must know both the theory and the evidence (Five major, 2003).

See Also:
Common Anti-Evolutionist Arguments
The Evidence for Evolution
Predictions and the Theory of Evolution
Falsifiable Elements and the Theory of Evolution
Frequently Asked Questions

Books

cover
cover
cover

For more books
on atheism
please visit
Atheist Books