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Randomness in Evolution: Valid and Invalid Usage

Walter Wayne said:
I agree with that mijo definition is useless, but I'm am wondering why you think by most other definitions evolution is not random, or at least which of those definitions would you think would not apply?
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Here's a typical definition of random: "Lack of predictability, without any systematic pattern."

Something like that is what most people mean when they use the word. And that clearly does not apply to evolution - evolution is very predictable in many ways, and it follows patterns that we are quite capable of understanding. Of course its details are not predictable (which is the case for ALL OTHER physical processes too), but many broad patterns are - increase in complexity over time, survival of the fittest rather than the least fit, general characteristics of responses to changes in the environment, etc.
 
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sol invictus said:
It doesn't sound like I misunderstood you at all - what you just said in the quote above is what I spent quite a number of posts trying to explain to you in the previous thread. I'm glad I got through.

So it sounds like we agree - your definition of random is useless since it defines all physical processes as random, and hence the statment "evolution is random" is empty. More useful definitions exist (and in fact are the ones used by everyone but you), and according to most of those, evolution is not random.
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No, we in fact do not agree.

Again, saying that evolution by natural selection is random simply because mutation is random does yield a meaningless statement in terms of physical systems ; however, saying that evolution by natural selection is random because there are not two distinct distinct groups of phenotypes, one that guarantees the production of reproductively viable offspring and one that precludes the production of reproductively viable offspring, does not yield a description that is useless for describing evolution by natural selection.
 
sol invictus said:
Here's a typical definition of random: "Lack of predictability, without any systematic pattern."

Something like that is what most people mean when they use the word. And that clearly does not apply to evolution - evolution is very predictable in many ways, and it follows patterns that we are quite capable of understanding. Of course its details are not predictable (which is the case for ALL OTHER physical processes too), but many broad patterns are - increase in complexity over time, survival of the fittest rather than the least fit, general characteristics of responses to changes in the environment, etc.
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Here's a typical definition of "theory": "[a]n assumption based on limited information or knowledge; a conjecture".

By the logic you just displayed, evolution by natural selection is a conjecture or guess.

Of course, that is not how scientists how scientists use the word "theory", but we're going to ignore that because we have decided to go with the common definition of "theory".:rolleyes:
 
UnrepentantSinner said:
So mijo, I guess you're unwilling to accept that "mutation is random but evolution is not"?
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Not unless you can describe how natural selection guarantees survival to all individuals possessing one group of phenotypes while it denies to all individuals possessing another group of phenotypes.

That is to say, that you have predicated your question on the idea that I understand random to mean "unbiased". I do not accept your premise for the meaning of "random", so I reject the conclusion drawn therefrom.
 
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I know that articulett likes to say that I am unintelligible to discredit me, so in the spirit of intelligibility, I present to a bulleted list the essentials of my position in it:

  • Deterministic evolution by natural selection divides the phenotypes in a population into two mutually exclusive groups individuals in which either
    1. all produce reproductively viable offspring or
    2. all produce fail to reproductively viable offspring.
  • Stochastic evolution by natural selection allows each phenotype to confer a probability of producing reproductively viable offspring on each individual that possesses it.

Note: In stochastic evolution by natural selection, it is possible for an infinite number of phenotypes to confer a probability of producing reproductively viable offspring of 0. It is also possible for a phenotype to confer a probability of producing reproductively viable offspring of 1.
 
Not unless you can describe how natural selection guarantees survival to all individuals possessing one group of phenotypes while it denies to all individuals possessing another group of phenotypes.
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NOTA BENE deterministic with respect to is not the same as wholly determined by - yes mijo, I am thinking of you and your twins. Their form does not wholly dictate their selection but to argue that their selection is not deterministic with respect to it would be WRONG.
 
cyborg said:
NOTA BENE deterministic with respect to is not the same as wholly determined by - yes mijo, I am thinking of you and your twins. Their form does not wholly dictate their selection but to argue that their selection is not deterministic with respect to it would be WRONG.
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You are redefining "deterministic" in a way that is not used by either scientists or mathematicians and that by defintion make evolution deterministic.

Your definition is invalid.
 
Seriously some of the people who are arguing that evolution is not random are more skilled at equivocating than creationists.
 
mijopaalmc said:
Not unless you can describe how natural selection guarantees survival to all individuals possessing one group of phenotypes while it denies to all individuals possessing another group of phenotypes.

That is to say, that you have predicated your question on the idea that I understand random to mean "unbiased". I do not accept your premise for the meaning of "random", so I reject the conclusion drawn therefrom.
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That statement is incorrect. A mutation does split the individuals in a population into 2 groups. But the members of one group do not all die while the members of the other group survive.
The survival of individuals in each group depends on their "fitness" to their environment. The mutation will allow individuals in one group more opportunity to reproduce than individuals in the other group. So in the next generation one group of phenotypes is more likely than the other.
 
Reality Check said:
That statement is incorrect. A mutation does split the individuals in a population into 2 groups. But the members of one group do not all die while the members of the other group survive.
The survival of individuals in each group depends on their "fitness" to their environment. The mutation will allow individuals in one group more opportunity to reproduce than individuals in the other group. So in the next generation one group of phenotypes is more likely than the other.
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I think you're missing the point of the post. Evolution by natural selection is not deterministic unless phenotypes are divided in to the two mutually exclusive groups mentioned above.

By the way, you explanation is inherently probabilistic and therefore described evolution by natural selectionasa stochastic (or random) process.
 
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sol invictus said:
I'm pretty sure you finally admitted somewhere that this definition applies to everything in the real world, making it useless. Have you forgotten that? Want me to dig up your quote?



Semantic debates are soooo boring.

Take 10^23 molecules of gas in a sealed box with volume 1 cubic meter. Start them all moving to the left at 10 m/s, and color one of them red. Where will the red molecule be in an hour?

That system is deterministic and causal (if we ignore quantum mechanics, at least). And yet the question is impossible to answer by any (even hypothetical) means. So, we treat our ignorance the same way we treat fundamental acausality: we call the result random.
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Yay!
 
Wowbagger said:
Well, there are five bullet points in my opening post...



Perhaps it might pay to clarify these things, for those who need it:

Mitchell's definitions of Random (summarizing the bullet points in the OP):
1. Analagous to "indifferent"
2. A stochastic model
3. A "happy accident"
4. Quantum uncertainty
5. Arthur Dent's daughter

There could be others.
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6. Arthur Dent falling, missing the ground and flying!
 
mijopaalmc said:
But "chaotic" does not mean "random". A chaotic system is by definition deterministic but sensitively dependent of initial conditions. A random system is by definition not deterministic.
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And that is nice in word space where we can say with certainty what something is. But you are putting the cart before the hosre in reality.

How will you tell a chaotic system from a random system without a lot (and I mean ahuge amount of study)?


So yes in word spece that has meaning, in reality it doesn't.

The atoms/molecule in in Sol Invinctus' example is subject to a very chaotic process, but it is essentially random in expression.

Ooops, i just made a mess in word space too!
 
mijopaalmc said:
I think you're missing the point of the post. Evolution by natural selection is not deterministic unless phenotypes are divided in to the two mutually exclusive groups mentioned above.

By the way, you explanation is inherently probabilistic and therefore described evolution by natural selectionasa stochastic (or random) process.
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Yes they are mutually exclusive as I said. However individuals in both groups survive and reproduce.

A stochastic process is one whose behavior is non-deterministic in that a state does not fully determine its next state.
Evolution is a multi-stage process involving populations. One stage is that some members in that population undergo mutations. Many mutations (e.g. point mutations) are random. A mutation is an event (not a process) and therefore is not a stochastic process. Evolution by natural selection as a whole can be described as a stochastic process but not mutation.
 
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mijopaalmc said:
You're missing the point yet again. Randomness can be tested in the lab (and in fact been tested to an absurdly high degree in the case of quantum mechanics).



Evidence of randomness's presence is identical initial conditions yielding different final conditions. This is how randomness is defined mathematically and scientifically. you are failing quite spectacularly at understanding this.
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Um, sorry, to our current knowledge QM is 'random' at some point we might have more knowledge and then in word space

QM might be
-random
-chaotic-stochastic-deterministc

I don't recall seeing anything that said that he process underlying QM was random, just that it follows some sort of proability that at this time we say 'is considered to be random'.
 
sol invictus said:
Here's a typical definition of random: "Lack of predictability, without any systematic pattern."

Something like that is what most people mean when they use the word. And that clearly does not apply to evolution - evolution is very predictable in many ways, and it follows patterns that we are quite capable of understanding. Of course its details are not predictable (which is the case for ALL OTHER physical processes too), but many broad patterns are - increase in complexity over time, survival of the fittest rather than the least fit, general characteristics of responses to changes in the environment, etc.
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I am not arguing with your here but the genome is blind to the enviroment, so the expression of traits is deterministic, however the traits of beings in enviroments and which traits will be expressed is contingent and essentially random.

So the expression of traits is very deterministic in outcome, the availability of traits and which enviroments they will end up in and how they might have benefit to beings is essentially "lack of predicatbility and without systemic pattern", although the traits will be localized for some populations and so the potential expression of traits in an unknown enviroment might show some branching structures.

The genome is blind to the enviroment and as such the future expression of traits in a changing landscape might be characterised as random.
 
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mijopaalmc said:
No, we in fact do not agree.

Again, saying that evolution by natural selection is random simply because mutation is random does yield a meaningless statement in terms of physical systems ; however, saying that evolution by natural selection is random because there are not two distinct distinct groups of phenotypes, one that guarantees the production of reproductively viable offspring and one that precludes the production of reproductively viable offspring, does not yield a description that is useless for describing evolution by natural selection.
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I would say that some parts of evolution are random because th egenome is blind, the future expression of traits in a changing landscape is not predictable.
 
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