Theory of Evolution is a Tautology

[ronan]

Wikipedia:

In biology, evolution is the process of change in the inherited traits of a population of organisms from one generation to the next. The genes that are passed on to an organism's offspring produce the inherited traits that are the basis of evolution. Mutations in genes can produce new or altered traits in individuals, resulting in the appearance of heritable differences between organisms, but new traits also come from the transfer of genes between populations, as in migration, or between species, in horizontal gene transfer. In species that reproduce sexually, new combinations of genes are produced by genetic recombination, which can increase the variation in traits between organisms. Evolution occurs when these heritable differences become more common or rare in a population.

There are two major mechanisms driving evolution. The first is natural selection, which is a process causing heritable traits that are helpful for survival and reproduction to become more common in a population, and harmful traits to become more rare. This occurs because individuals with advantageous traits are more likely to reproduce successfully, so that more individuals in the next generation inherit these traits. Over many generations, adaptations occur through a combination of successive, small, random changes in traits, and natural selection of those variants best-suited for their environment. In contrast, genetic drift produces random changes in the frequency of traits in a population. Genetic drift results from the role chance plays in whether a given individual will survive and reproduce. Though the changes produced in any one generation by drift and selection are small, differences accumulate with each subsequent generation and can, over time, cause substantial changes in the organisms.

When you loook at:

natural selection, which is a process causing heritable traits that are helpful for survival and reproduction become more common in a population, and harmful traits to become more rare

It says that natural selection cause helpful traits (defined as the one who help for reproduction and survival) to survive :P

It is a tautology
So it is true but it is not helpful at all

[James R]

It would be tautological if the only content of the theory of evolution was that "The fittest survive" and "The fittest are defined to be those who survive".

However, the definition of "fitness" is not simply "those which survive must have been 'fit' and those which didn't weren't". Rather, "fitness" is defined by the environment in which organisms live and interact.

Natural selection says that those organisms that are better adapted to their environment are more likely to survive and reproduce than those who are not so well adapted. Notice that this is a prediction, and not something that is determined after the fact by looking at which creatures survived and which did not.

[S.A.M.]

Hmm I think fitness is defined by reproductive fitness. Those who reproduce can survive.

[Cris]

Dinosaurs had no trouble with reproduction but they could not adapt to massive environmental changes.

[ronan]

However, the definition of "fitness" is not simply "those which survive must have been 'fit' and those which didn't weren't". Rather, "fitness" is defined by the environment in which organisms live and interact.

Natural selection says that those organisms that are better adapted to their environment are more likely to survive and reproduce than those who are not so well adapted. Notice that this is a prediction, and not something that is determined after the fact by looking at which creatures survived and which did not.

It is still a tautology because environment is present in the definition of both fitness and the one who survived.

What is the meaning of "organisms which are adatped to their environment"
except that "they are more likely to survive and reproduce in this environement"

It is really a tautology, the conclusion/prediction "organisms are more likely to survive and reproduce in this environment" is included in the statement: "organisms are adatped to their environment"

Else what would be the meaning of being adapted to an environment?

[iceaura]

It is really a tautology, the conclusion/prediction "organisms are more likely to survive and reproduce in this environment" is included in the statement: "organisms are adatped to their environment"

The role of time is different.

Evolutionary theory does not say "these organisms are more likely to survive and reproduce, therefore they are better adapted ", or vice versa. That would be projecting into the future. The future is unknown. We don't know if the beings we see are well adapted to next year's world, regardless of their current reproductive advantages.

Evolutionary theory explains the present in terms of the past, not the future in terms of the present. Although it can be used to project or predict a little, it's the origin rather than the fate of species that is its subject.

[ronan]

Evolutionary theory explains the present in terms of the past, not the future in terms of the present. Although it can be used to project or predict a little, it's the origin rather than the fate of species that is its subject.

Why you talk about time, the tautology is atemporal. it works in both sense.

Let's see:

To say that "organisms are adatped to their environment" (present) is to say that "they are more likely to survive and reproduce in this environement" (future)

To say "organism survived and reproduced" (present) is to say that "they were more adapted to their environment" (past)

You see, both are tautologies

[spidergoat]

Not all those that survive are equally fit. There is a variable degree of fitness due to the variations within the genome. One may reproduce, but the offspring may be fewer and weaker, and thus not fit so well to the current environment. But the environment could undergo change which makes the less fit organisms flourish. In the long term this guides the adaptations that become more common.

[andbna]

Consider this:
I have two bacteria, a blue and a green culture. The green contains a gene which can neutralize certain Penicillin. The blue does not.
I place these 2 cultures into the same environment (some Petri dish with a soy mixture)
I notice that each type makes up 50% of the total culture.

I now add the aforementioned penicillin to the environment and come back a week later. If I apply the law of natural selection, would I expect culture blue or green to be dominant?
Green; and since I have been able to make a prediction, it is not a tautology.

Feel free to experiment.
-Andrew

[Myles]

Hmm I think fitness is defined by reproductive fitness. Those who reproduce can survive.

You have already gone down that road on another thread. The dinosaurs reproduced as did many animals which have become extinct. You have been given a correct answer ; try and understand it because what you think is irrelevant owing to your woeful lack of understanding of evolutionary theory.

[Pete]

The fundamental notion of evolution is tautological in a way- the same way that "I think, therefore I am" is tautological.

This kind of tautology is really an obvious truth.
The notion that "forms which reliably reproduce themselves are likely to persist" is just as obviously true as "I think, therefore I am."

[ronan]

The fundamental notion of evolution is tautological in a way- the same way that "I think, therefore I am" is tautological.

This kind of tautology is really an obvious truth.
The notion that "forms which reliably reproduce themselves are likely to persist" is just as obviously true as "I think, therefore I am."

Right

and since I have been able to make a prediction, it is not a tautology.
-Andrew

It is still a tautology, it is self evident
The prediction arise from the fact that you know the tautology which is self evident AND the fact that you know that "the green bacteria contains a gene which can neutralize certain Penicillin."

Be careful to be aware of your premises before concluding

[Pete]

Of course, being tautological (in the stated sense) doesn't mean it isn't useful.

On the contrary, this particular truth has very powerful consequences, and a profound impact on our understanding of the world.

Although I called it an "obvious truth" earlier, you shouldn't forget that this "obvious truth" and its implications for the development of complex forms from simpler forms was not recognized before Darwin.

[ronan]

So we agree now, theory of evolution is a tautology

right it help to see the world in special manner

The consequence a you said has a profound aspect on our view of the world but it is also why people find it very dangerous because it is a ideology that as any tautology in mathematics coudl be replaced by another tautology.

a tautology is a view of the world, not the world.

Another tautology: god created the species (god= creator, species = creation )

[Pete]

So we agree now, theory of evolution is a tautology

No. A fundamental idea of the theory of evolution is (in a way) a tautology. More correctly, it's an obvious truth.
Obviously, not all obvious truths have the same meaning - you can't generally substitute one for another in any meaningful way.

Descarte's "I think, therefore I am" is a tautology (with obviously different meaning to "forms which reliably reproduce are likely to persist"). His "Discourse on Method" is not.

[Pete]

Another tautology: god created the species (god= creator, species = creation )

That's not a tautology unless you arbitrarily change the meaning of words (a useless exercise). Here's a useless tautology for you:

The cause of life on Earth is what caused life on Earth.

You might be tempted to substitute some other word for "The cause of life" (eg "god", "evolution", "aliens", "abiogenesis from RNAP"). But if you do so, then the sentence is no longer a tautology - "the cause of life" is given non-tautologous attributes.

[iceaura]

To say that "organisms are adatped to their environment" (present) is to say that "they are more likely to survive and reproduce in this environement" (future)

To say "organism survived and reproduced" (present) is to say that "they were more adapted to their environment" (past)

You see, both are tautologies

You seem to be defining the word "adapted", rather than describing a tautology. Others would define it differently - pointing out that sexual selection, for example, often gives evolutionary advantage to non-adaptive traits.

[ronan]

No. A fundamental idea of the theory of evolution is (in a way) a tautology. More correctly, it's an obvious truth.
Obviously, not all obvious truths have the same meaning - you can't generally substitute one for another in any meaningful way.

Descarte's "I think, therefore I am" is a tautology (with obviously different meaning to "forms which reliably reproduce are likely to persist"). His "Discourse on Method" is not.

More correctly?
Tautologies of course are obvious truth, this statement is itself a tautology

I never say they have the same meaning, that was in fact my point, that two tautologies result in different conceptual world.

The point is that because it is a tautology it should not be considered as giving us information about the reality, it is only a view of reality like saying that god created the universe, nobody can deny this if god is defined as creator.

"forms which reliably reproduce are likely to persist" : the linking verb "are" is not denyable
but it is so obvious that it does not help
The only thing that is not obvious is that forms are said to reproduce as well as to fail to reproduce. (something that everybody knew before)

That's not a tautology unless you arbitrarily change the meaning of words (a useless exercise). Here's a useless tautology for you:

The cause of life on Earth is what caused life on Earth.

You might be tempted to substitute some other word for "The cause of life" (eg "god", "evolution", "aliens", "abiogenesis from RNAP"). But if you do so, then the sentence is no longer a tautology - "the cause of life" is given non-tautologous attributes.

look:
"forms which reliably reproduce are likely to persist"
and
"The cause of life on Earth is what caused life on Earth."

both do not give any information. evrything is included in the premise,

true, meanign differ, one is talking about the existence of a cause of life on earth while the other is talking about the fact that forms reproduce with uncertainty
that's it!

[Pete]

Consideration of that obvious truth opened up some very productive lines of thinking that led to testable hypotheses about life on Earth.
Have you read On the Origin of Species

[ronan]

Consideration of that obvious truth opened up some very productive lines of thinking that led to testable hypotheses about life on Earth.

I have to recognize that my openning post was too provocative (it was done in purpose):
"It is a tautology
So it is true but it is not helpful at all"

But my point was that the theoory of evolution should not be stated as a fundamental aspect of the universe that answer everything about life and the origin of species, it is only an obvious truth, a tautology (for using a more provocative word) that brings a particular point of view.

Have you read On the Origin of Species?

No, I did not read it, but it is one of many books that I would probably enjoy to look at it, whenever it will happen.