We've all heard the argument,
"Evolution is JUST a theory, it's not a fact",
or some variation there of.
Unfortunately, making such a claim exposes you as profoundly ignorant
of biology, evolution, and science in general, as that statement is wrong for two reasons.
First, it shows that not only do you not know what the theory of evolution is
(which should be enough to stop anyone from arguing against it
until they've at least read a textbook or two)
but second you don't even know what the words "theory" and "fact" mean.
So, what do the words theory and fact mean?
Well, a scientific fact is generally a verifiable observation,
such as "what" just happened,
and this is roughly the same as the common usage of the word fact.
A scientific theory is an idea that explains all relevant facts,
essentially "how" did something happen,
but this usage is almost the diametric opposite of the common usage
where theory is synonymous with a guess.
Theories are ideas that explain facts,
therefore, theories cannot be facts.
Arguing that evolution is a theory not a fact
is like arguing this is a book, not a word,
or this is a parking garage, not a car.
It's silly because it shows you don't know
what the words you're arguing against even mean.
One of the biggest problems people have with the theory of evolution
is understanding the scientific meaning of the word theory.
The concept that one word can apparently have more than one meaning
is clearly alien to many creationists.
So to help them out I've arranged a little exercise
geared specifically for those who are proficient in English.
I will read a sentence aloud and you will try to guess what I mean.
Okay, sentence 1:
That girl is very hot.
Now do I mean A) That girl has a very high temperature, or B) That girl is attractive?
Sentence 2: That frying pan is very hot.
Now do I mean A) That frying pan has a very high temperature,
or B) That frying pan is attractive?
I'm pretty sure everyone said B for sentence 1 and A for sentence 2,
as we all learned as far back as elementary school that words can have multiple meanings
and we must use the context of the sentence to figure out which meaning is most appropriate.
So with that in mind let's try another example.
If I say: All the kids in the class had their own theory of who stole the exam,
versus: After many years of work Dr. Smith had formulated a theory
to explain the thousands of relevant scientific studies.
It pretty clear that the word theory is being used in two different ways.
In the first sentence it is being used according to its colloquial definition,
which is synonymous with the word guess,
all the kids had their own guess as to who stole the exam,
while in the second sentence it is being used according to its scientific definition,
Dr. Smith's theory is supported by thousands of facts
and refuted by none, it is therefore far from a guess.
Is it really that hard of a concept,
when discussing science you use the scientific definition of the word theory,
when discussing an everyday event you use the common usage of the word theory.
Arguing that Evolution is JUST a theory,
shows that you don't even understand the scientific meaning of the word theory,
let alone what the theory of evolution is.
Arguing from ignorance is intellectually dishonest.
I would like to add that I've actually had some creationists argue
that when Darwin first proposed the theory of evolution,
the word theory ONLY meant a guess,
and it was later that scientists, realizing the weakness of their idea,
changed the meaning of the word theory to give evolution more credence.
I'm sorry, some people may be ignorant, and others willfully so,
but making such an argument puts you in a class apart from all others.
Now to the second half of the quote "it's not a fact".
Well, as we saw earlier, a scientific fact is a verifiable observation.
So, has evolution been observed?
Absolutely.
Scientists have directly observed instances of microevolution
such as the HIV virus mutating to become resistant to drugs.
Scientists have directly observed instances of macroevolution
such as the evolution of entirely new species of mosquito, flies, and flowering plants.
Scientists have directly observed beneficial genetic mutations
that increase the information content in DNA
and produce entirely new enzymes such as the nucleotide insertion
that gave rise to nylonase in a species of Flavobacteria.
Scientists have directly observed the evolution of multicellular life from unicellular life
such as in the predation experiment involving Chlorella vulgaris.
Scientists have directly observed the evolution of new structures
such as the formation of cecal valves in the Italian Wall lizards.
Scientists HAVE directly observed every aspect of evolution.
Therefore it IS a fact that species evolve.
Evolution IS a FACT when describing WHAT happened.
It is the theory of evolution that seeks to explain HOW things happened.
How do species evolve?
The theory of evolution includes genetic mutations, natural selection, genetic drift,
and sexual selection as mechanisms for the observed instances of evolution.
If you are a bit confused as to how something can be both a theory and a fact,
again, remember that words can have more than one meaning.
But just like evolution, the word gravity is both theory and fact.
It is a fact that objects fall.
Objects with mass gravitate towards one another.
That has been directly observed. That is a fact.
The theory of gravity seeks to explain why objects with mass attract one another.
Currently Einstein's theory of General Relativity which proposes that objects with mass
warp the fabric of spacetime is the best explanation we have for all the observed facts.
Finally, some creationists will add that evolution can never be proven.
This again exposes their profound ignorance of the sciences
as NOTHING in reality can ever be proven 100%
as a new piece of evidence can always come along in the future
to disprove any current idea.
So no, the theory of evolution can never be proven 100%,
And neither can the theory of gravity
Or Atomic theory
Or Germ theory
Or the theory of heliocentrism,
you know, that idea that the sun is the center of the solar system.
Evolution is a theory, the highest status an idea can ever reach in science,
because it is currently supported by over 240,000 scientific peer reviewed articles,
containing millions of independent verifiable facts,
collected by tens of thousands of scientists,
working over the past century and a half.
It is disproved by none, and no better ideas have yet to be proposed.
But evolution, the direct observation that species do change over time, is also a verifiable fact.
So the next time a creationist makes the argument
"Evolution is JUST a theory, it's not a fact",
you'll know to correct them,
that evolution is both a theory and a fact
Think about it.