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What evidence is there for evolution being non-random?

Myriad said:
There's another reason to object to the overarching statement "evolution is random," besides the misrepresentation of the import of that statement by Creationists. It really can be a barrier to understanding evolution.

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Similarly, if the key question someone has about evolution is, as it so often is, "how could evolution have generated humans starting only with microbes?" then an answer that begins "when you have some genomes mutating randomly..." is not a good answer. It's the wrong level of description for the phenomenon you're interested in.

If your starting point for understanding evolution is "it's a random process," it announces right off the bat that you're going to be looking at the process at the wrong level of description to explain the "big picture" aspects effectively,
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On the other hand...

Your last post mentioned that one of the predictable consequences of evolution was widespread diversity of life. I would contend that understanding the randomness of evolution is a key component of understanding how that diversity arises. Furthermore, that randomness occurs in both the mutation and selection aspects of evolution. A population of animals that is split into two groups by some natural calamity (a random event) will experience different selection pressure if the two groups are geographically separated in different environments. (e.g a few individual snakes end up on an island, while the others end up on the mainland.) Even before any effects of mutations are applied, the genetic characteristics of the two subgroups will evolve differently for the two groups. The organisms may very well evolve into two different varieties even with no mutations. (Someone more knowledgeable than I will have to discuss whether such a situation could actually produce two different species without mutation.)

So, it depends on exactly which "big picture" aspects you are looking at. If you are trying to figure out how a given organism got to be the way it is, randomness isn't a very useful factor in explaining things. If you are trying to figure out how there got to be so many different sorts of organisms, randomness is essential to comprehension.
 
Mijopaalmc said:
So you're saying that we should describe evolution not just inaccurately, but contrafactually, because an accurate and factual description will confuse people?
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Are you suggesting that the simple statement "evolution is random" is accurate, factual, and illuminating? If so, then describing anything as random is just as good. What does this accomplish?

At least say "evolution is a random process." That makes it sound more technical and perhaps allows the listener to realize that you're using a technical meaning of "random."

~~ Paul
 
Meadmaker said:
I think there's a psychologically interesting element about some people's aversion to describing evolution as "random" or "by chance", that goes deeper than any fear of inaccuracies in descrption. In my last post, I linked to an earlier post in which I gave two different descriptions of evolution. Factually, they were identical (or I tried to make them so), but they had different psychological impacts. I'd like to hear your comments on that post.
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I didn't really prefer one description over the other. They both gave a reasonable description of evolution, pointing out the variation aspect and the selection aspect. At no point did I think "Aha! I get it. Evolution is random."

I can't help but feel that I'm waiting for the other shoe to drop.

~~ Paul
 
Vorticity said:
Now Paul, that's unfair. We're not all T'ai Chis.
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Yeah, not everyone can be that good!

You gotta wonder about those who constantly view the world through the lens of others having motives. How depressing for them.

Great thread though! Glad to see others point out the obvious fact that stochastic is random, evolution is a stochastic process... and therefore the obvious conclusion.
 
T'ai said:
You gotta wonder about those who constantly view the world through the lens of others having motives. How depressing for them.
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I rarely do so. However, I don't believe we've heard the real reason why Meadmaker thinks it's so important to call evolution random.

Great thread though! Glad to see others point out the obvious fact that stochastic is random, evolution is a stochastic process... and therefore the obvious conclusion.
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Yeah, like that.

~~ Paul
 
T'ai said:
So you're saying evolution is a stochastic process, but not really?
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No, it's really a stochastic process. And if you would like to call it such when explaining it to a novice, be my guest. Then the novice can ask what a stochastic process is and expect to get a full explanation from you. For example, you might say "A system that evolves in time according to probabilistic equations ..."

After that you can explain that the weather is random.

~~ Paul
 
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Thaiboxer said:
That seems arbritrary to me. Why not say "If it ain't completely random, then it's deterministic"?
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Because the definition of a random process is that it has one or more random variables. For all intents and purposes, the definition of random is "not deterministic."

~~ Paul
 
Let me quote from The Penguin Dictionary of Mathematics:

"A variable X that may take any one of a finite or countably infinite set of real values, each with an associated probability, is a discrete random variable."

So there we have a definition of randomness based on varying probabilities. But now what about their definition of random by itself:

"A random sample of r items from n is a selection in which each item has an equal chance of selection. Thus, if we select four numbers at random from 1 to 20 without replacement the selections 1,2,3,4 and 3,16,7,19 are equally likely. Most people would not regard the first selection has haphazard, but they would the second."

Even in mathematics, the simple word random is used to mean randomness with equal probabilities.

Evolution is not "random."

~~ Paul
 
Paul C. Anagnostopoulos said:
Let me quote from The Penguin Dictionary of Mathematics:

"A variable X that may take any one of a finite or countably infinite set of real values, each with an associated probability, is a discrete random variable."

So there we have a definition of randomness based on varying probabilities. But now what about their definition of random by itself:

"A random sample of r items from n is a selection in which each item has an equal chance of selection. Thus, if we select four numbers at random from 1 to 20 without replacement the selections 1,2,3,4 and 3,16,7,19 are equally likely. Most people would not regard the first selection has haphazard, but they would the second."

Even in mathematics, the simple word random is used to mean randomness with equal probabilities.

Evolution is not "random."

~~ Paul
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Then by definition standardized test scores cannot be random as there is almost alway a range of values that they can take on. Therefore, you cannot rank people according to their percentile because such a process depends on having a random variable for a score and a random sample of the population of individuals who took the test.
 
Meadmaker said:
And I can't help but wonder why you feel that way.
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Because it is easier to question people's motives and attack their character than to actually address the argument. After all, if he fails to convince us by presenting evidence which he has done, he can always claim that we were creationists trying undermine evolution.
 
Dancing David said:
Taffer:

I apologise for all my extended responses.

The statement about the four balls in the box is the meaningful argument.

The motion and elasticity of the balls can be detrmined, but the system is not deterministic.

The interaction of determined individuals is not always deterministic.

I have not satted the ID argument that "all evolution is random", it is constrained variability in a complex interaction that creates randomness.
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That's ok, David, it's always nice to argue with people who know what they are talking about.

I appears to me that you are saying that, while some elements of evolution may not be random (selection with respect to the environment, or whatever), because many elements are random, it is better to call random then not. In other words, most processes of evolution, when combined, are some complex to be impossible to predict.

If this is what you are saying, then I agree with you.

I apologize for my bias. Statements like "evolution is random" have I heard too often in an ID context, and tend to set me on the defensive. :o
 
T'ai Chi said:
You're saying it is more not-misleading to call it deterministic?
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No, it is just as misleading to call it that.

Evolution involves many factors. While the end outcome, given an initial set of qualities, may be essentially random, and unpredictable, it is the few parts of evolution which act in a predictable way which make evolution possible.
 
Taffer said:
No, it is just as misleading to call it that.

Evolution involves many factors. While the end outcome, given an initial set of qualities, may be essentially random, and unpredictable, it is the few parts of evolution which act in a predictable way which make evolution possible.
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So you are saying that it is wrong to say that natural selection confers a specific probability of "survival" on an individual?
 
Meadmaker said:
Can anyone describe to me what it means when someone says "Selection is non-random."
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I don't think you are. But I think the OP is. And I gave my analogy. I think most of the people here understand and agree with the "random" parts of evolution.

Certainly you understand how artificial selection is not random. Humans choose and breed for traits they like while culling those they do not want in agriculture, dog breeding, horses, etc.

We don't call it random, because we are selecting the traits. In that way, natural selection is not random either. Although it has no consciousness, the environment selects the traits that survive and are built upon through time. If it's cold, those with thinker fur preferentially survive...if being venomous enhances survival...venomous animals become increasingly so. They are selected because they are less likely to be eliminated by prey. The fact that they are selected is not random--it's BECAUSE they have evolved something which allows them an "advantage" in the game of life.

In that way selection is not random. Sure, it's "random" that the first step towards venomous clicked in...and it's random that it happened to be usueful in some creatures survival and reproductive success--but it's not random that such a success could be built upon or would be advantageous. It certainly is not advantageous to the prey--except that it acts as a selection process upon them--those more immune to the poison preferentially survive--they are "selected for". It confuses things to call that selection "random" because it boils down to a semantic game when biologists don't really disagree on what is occurring.

It is clearer to say that mutations are random (more or less) while selection is not (more or less). It avoids the creationist semantic game though it doesn't stop the whole moving the goal posts thing. Creationists (which I believe mijo is) seem to equate "evolution is random" to the tornado in the junkyard analogy. I think that mijo is doing just that. But I can't tell because he's one of those semantic game players from my perspective. A series of coin tosses is random. If you got to keep the money every time you got five coin tosses in a row correct that would be akin to selection. Your growing wealth would be akin to evolution. Your lucky streaks would be random--but we can predict that given and endless number of coin tosses you would have lucky streaks and accumulate wealth. We could even predict the likely frequency of lucky streaks...and thus the accumulating wealth. We couldn't tell when the next lucky streak would come. But we could be assured that the environment of endless coin tosses would produce them regularly and that is "selection". Tossing random into the equation, muddies understanding. I would only use the word random to describe each coin toss--not what happens through time. Wouldn't you? Could you see how it might be confusing to call the whole process random...and that someone could reply that a wealthy person got wealthy by complete randomness of the coin tosses?

(forgive me for the coin toss analogy...I live in Las Vegas and our town is built on this sort of randomness--coupled with peoples' confusion about it--and the predictability of large numbers of "randomness". If the house has a two percent advantage--the more people play the more that advantage is accurate--and the bigger it is, as well--that is non-random "selection". The cards a person is dealt are random. We can't predict which patrons will win. We can predict that the house (environment) will win in the end.)
 
Paul C. Anagnostopoulos said:
Because creationists insist on saying "Evolution is random, so God musta done it."
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Going back to this quote, Paul, you are falling for the bait. Other posters have already alluded to this, but I'll add my two cents. This argument* works by setting up the trap. They say that, and they hook you in to quibbling about the premise. The premise, as we have noted is oversimplified, but basically correct. Meanwhile, you've let them get away with the fallacies in the rest of the argument.

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*It would be instructive to post an example of a real, honest to goodness, anti-evolution argument that takes this form, and see how disputing the randomness of evolution would affect the argument. What say you? Do you think you could find an example of the sort of argument that you worried about, so we could dissect it?
 
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