Evolution Not Random

[Kotatsu]

I think that you are missing my point. While you gave an example of a specific variant that never reproduces in the way that defined it, I am interested in whether, as a whole, a population divides neatly into a group of phenotypes that always (barring a catastrophic event) reproduces and a group of phenotypes that never reproduces.

Like ants and other social insects, you mean?

I think my example may still qualify. I may just have worded it clumsily, or my slight vagueness (1) may have given you the wrong impression.

The population which has the trait A could in some cases be neatly divided into two phenotypically distinguishable subgroups, A and A*, of which only individuals in subgroup A ma interbreed to get fertile offspring. Matings between the groups may give offspring, but this offspring will never be fertile, and in many cases, it only rarely survive to hatch (or similar).

Is it important that the difference between the subgroups is phenotypical, and if so, why?

---
(1) Though I am guessing that any biologists who are reading this may have figured out what I am thinking about, especially if they are familiar with what I usually talk about.

 

[zooterkin]

I asked if evolution was "based in probability". So, far you have not produced any evidence that it isn't.

No-one is denying that chance plays a part in evolution. If you're wanting people to say as a result that "evolution is random", however, I think you're going to have a long wait.

Why is it so important to you that such an over-simplified and misleading statement should be made, without qualification?

I am interested in whether, as a whole, a population divides neatly into a group of phenotypes that always (barring a catastrophic event) reproduces and a group of phenotypes that never reproduces.

And where are you going with this? Why do you think this is even a possible real-world scenario? I can think of some phenotypes that never* reproduce; I can't think of any that are guaranteed to always reproduce, though in ideal circumstances they may come close.


ETA: Looks like I may be thinking on the same lines as Kotatsu, whose post crossed with mine.

* Well, almost never.

 

[mijopaalmc]

Kotatsu-

What I am saying is that, if a hypothetical population has two phenotypes* A and B and all the individuals with A reproduce while none of the individuals with B reproduce, selection would be deterministic, because there is only one possibility for each phenotype. However, if some individuals with A reproduce while others don't and some individuals with B reproduce while others don't, the selection is stochastic because there is more than one possibility for each phenotype.

*phenotype is the characteristic on which natural selection act; not every allele therefore contributes to the phenotype, as some alleles are neither selected for or selected against.

 

[sol invictus]

What exactly is wrong with the definition of "random" as "[o]f or relating to a type of circumstance or event that is described by a probability distribution"?

What's wrong with it is

a) It's so general it applies to everything. As I already said, in the real world there is always uncertainty. Even the the orbit of a planet around the sun is random by this definition. A comet could fly in from space and perturb the orbit. The sun could go nova and destroy it. These possibilities can be described by prob. distributions. Therefore according to you the motion of the earth around the sun is random.

b) It does not correspond to the standard definition. That's clear, since according to you evolution is random, but according to the Oxford English Dictionary, Richard Dawkins, and just about everyone else, it's not.

No one (as far as I know) disagrees that evolution is random according to your definition - they are just arguing that your definition is bad. (And by the way, there is absolutely no reason - other than intimidation - to mention Lebesgue measure or Armand Borel in this thread. They are utterly irrelevant.)

 

[Kotatsu]

Kotatsu-

What I am saying is that, if a hypothetical population has two phenotypes* A and B and all the individuals with A reproduce while none of the individuals with B reproduce, selection would be deterministic, because there is only one possibility for each phenotype. However, if some individuals with A reproduce while others don't and some individuals with B reproduce while others don't, the selection is stochastic because there is more than one possibility for each phenotype.

*phenotype is the characteristic on which natural selection act; not every allele therefore contributes to the phenotype, as some alleles are neither selected for or selected against.

I am a working biologist, and understand what a phenotype and an allele is.

The examples I am thinking about seems permissible to use under these circumstances. I still have some questions, though:

1) Do you require the basis of the phenotypical difference to be a difference in absolute sequences, or can other kinds of differences also be considered, as long as one individual can only have one phenotype, that is, as long as the difference in phenotype is not determined environmentally or seasonally?

2) I want to have it made clear whether or not a mating between A and B which can only result in infertile offspring would count or not. Similarly, if offspring was theoretically fertile, but never lives long enough to hatch, or never lives long enough to mature, does this count?

3) What is the difference you perceive between your notation of phenotypes A and B, and my notation of phenotypes A and A*?

4) When you say "if some individuals with A reproduce while others don't and some individuals with B reproduce while others don't, the selection is stochastic because there is more than one possibility for each phenotype", does this mean that A and B may not interbreed, regardless of the fertility of the outcome, or that B may not breed with other Bs, regardless of the fertility of the outcome?

5) Do you require a physical (or other) impossibility for B or A* to breed, or is it sufficient if they simply never get selected by a mate?

 

[Wowbagger]

What exactly is wrong with the definition of "random" as "[o]f or relating to a type of circumstance or event that is described by a probability distribution"?

Keep in mind that:

1. random variables are defined on a probability measure
2. the continuous functions of elementary algebra and calculus are defined on the Jordan measure or the Lebesgue measure
3. the replacement of a variable with a random variable, as sol invinctus suggested, does not turn a deterministic process into a stochastic process, because the random variables would not necessarily be defined on the same measure space, or even the same measurable space.

Reality is NOT random, like that!!!

We have been over this before: You must separate the real world from the provisional model.

There seem to be no probabilistic random variables, like those you define, in nature. This is demonstrated by the fact that, the more precisely we study Evolution, the less randomness we find!!

Granted, many of our models still use lots of random variables in them, but one-by-one, they are disappearing. This is not a trend consistent with the notion that Evolution is "random".

It is more consistent with the notion that humans are not born with the ability to obtain "perfect" information about the Universe, all at once.

 

[Belz...]

But the point is that nothing can be "constrained and biased to the point of deterministic". If there is at least one other possible outcome, even if it has a probability of 0, the system is "stochastic" or "random". "Stochastic", or, to a lesser extent, "random", is truly the most rigorous term that can be used to describe, and all the obfuscating and equivocating that articulett attempts will not make that false.

There IS only one outcome. Unfortunately we don't have all the data, ergo it's "random" from our point of view. Selection, however, is another matter.

 

[Belz...]

But my question has always been: what evidence is there for evolution being mathematically deterministic (non-random)?

What do you mean by "mathematical" ?

Poker contains randomness but not the same sort of randomness as roulette.

And certainly not the same randomness we find at the quantum level.

Random and deterministic are relatively useless terms unless defined or related to something.

If the terms are useless, than why is the OP about the terms?

Translation: "I stopped reading after 'useless'"

 

[Belz...]

Per Mijo's definition evolution IS random. And so are you. So is Poker. So is monopoly. So is whether seat belts save lives. If it has anything to do with probability in any way-- it's random to Mijo.

There is no such thing as "'mixed' random and deterministic processes".

What do you mean by "random", then, Mijo ? Random as in, quantum random... or random as in "deterministic but we don't know the outcome" ?

 

[Meadmaker]

Just in case anyone doesn't understand the genesis of this thread, it all started back during a discussion of Dawkins' comments about chance in Chapter 4 of "The God Delusion". (Or was it chapter 3, I forget). Some people commented about it in a generally amicable way, until someone accused mijo of being a creationist.

It was a stupid accusation, but it made him mad.

From there, it went downhill. The same stupid accusations continue to be thrown about, and it still makes mijo mad.

The nature of evolution and the randomness thereof could be an interesting discussion, but if you ever want to engage in such a discussion in a reasonable fashion, everyone involved will have to pounce on the personal insults being thrown about, even if they are thrown by someone on "your team". If you see someone accusing someone else of being a creationist , please, say something. It ought to be stopped.

 

[Meadmaker]

There seem to be no probabilistic random variables, like those you define, in nature.

FWIW, the general feeling among physicists is that there are, in fact, random variables in nature. At the quantum level, it appears that things are truly random, and no amount of observation will ever discover why, for example, an atomic nucleus decays when it does.

Furthermore, those quantum fluctuations are inputs to chaotic systems, and their effects are magnified, having macroscopic effects, which means that really, the universe would then work in a truly random manner.

As an illustration, the universe consists almost entirely of matter, with very little anti-matter. Why? Quantum fluctuations, or to put it differently, matter won the coin toss. It was a random event.

Lots of similar random events end up affecting the course of evolution.

 

[cyborg]

To repeat my previous comments on the matter:

"Egg frying is a random process because it may not end with a successfully fried egg due to inherent physical randomness that prevents the outcome of the process being known"

"Egg frying is a deterministic process that consists of placing a frying pan on a stove, heating the frying pan, placing a suitable fat/oil into the pan and heating it, cracking an egg open into the pan and heating it."

 

[Wowbagger]

FWIW, the general feeling among physicists is that there are, in fact, random variables in nature. At the quantum level, it appears that things are truly random, and no amount of observation will ever discover why, for example, an atomic nucleus decays when it does.

Furthermore, those quantum fluctuations are inputs to chaotic systems, and their effects are magnified, having macroscopic effects, which means that really, the universe would then work in a truly random manner.

As an illustration, the universe consists almost entirely of matter, with very little anti-matter. Why? Quantum fluctuations, or to put it differently, matter won the coin toss. It was a random event.

Lots of similar random events end up affecting the course of evolution.

Ah, yes, at the Quantum level, you could say there are some "truly random" things going on. However: Those random things hardly make an impact beyond the quantum level, because the probabilities smear out, at coarse grained levels.

In other words: It doesn't matter how "random" quantum stuff is. The general trend of those random variables end up generating a very predictable picture, for us, in the end.

Water tends to go down waterfalls. Perhaps, on very rare occasion, one or two molecules go up the waterfall (perhaps it caught a wind in just the right manner), but the general trend is clearly downward.

 

[mijopaalmc]

Wowbagger-

The "general trends" of which you speak do not, by their very existence, require a deterministic system. In fact, convergence of an increasing number of trials towards an expected value with decreasing error is a cornerstone of probability and statistics, summarized in the central limit theorem and the laws of large number, which have all been generalized to include cases where the random variables are not identically and independently distributed.

I would also reiterate that my original argument was that there is not sufficient evidence from empirical observation of evolution to rule out its being random.

 

[mijopaalmc]

"Egg frying is a random process because it may not end with a successfully fried egg due to inherent physical randomness that prevents the outcome of the process being known"

Straw man.

No-one has said that the end state in unknowable. The egg will end up fried. We have merely claimed that you cannot know the exact end state (e.g., the shape the white will take given the initial conditions.

"Egg frying is a deterministic process that consists of placing a frying pan on a stove, heating the frying pan, placing a suitable fat/oil into the pan and heating it, cracking an egg open into the pan and heating it."

Straw man.

Having an orderly process does not make the process deterministic. If you were to perform two trials each of 100 rolls of a six-sided die, sum the first roll from the first trial and the first roll from the second (and so on), and select the rolls based on whether they were between 6 and 11, you would have an orderly process with a random outcome.

 

[cyborg]

You don't know what a straw-man is.

No-one has said that the end state in unknowable. The egg will end up fried.

What if the gas goes off?

What if I'm out of oil or eggs?

We have merely claimed that you cannot know the exact end state (e.g., the shape the white will take given the initial conditions.

It is one thing to claim that ignorance of variables will lead to uncertainty it is another to then say "this is therefore random".

That is a meaningless statement. You refuse to acknowledge this.

Having an orderly process does not make the process deterministic.

This is exactly what it means to be deterministic.

If you were to perform two trials each of 100 rolls of a six-sided die, sum the first roll from the first trial and the first roll from the second (and so on), and select the rolls based on whether they were between 6 and 11, you would have an orderly process with a random outcome.

And if I did the same thing with a long list of numbers from 1-6 where I read off each value nothing about the process will have changed.

Input -> Function -> Output

Why exactly you think it is meaningful to describe the nature of a function by the nature of the inputs one may choose to provide it is beyond me.

 

[Belz...]

Straw man.

Straw man.

Do you even know what those are ?

 

[Wowbagger]

I would also reiterate that my original argument was that there is not sufficient evidence from empirical observation of evolution to rule out its being random.

I was not "ruling out" that anything was random.

But, as far as science is concerned, it adds nothing to claim it is. You can't make predictions on stuff that is random. It certainly is not any more instructive to claim evolution is "random" than anything else we know of, (beyond the quantum level*) such as the weather.

If you are trying to make the point that we don't know everything, about life, the Universe, and everything, and therefore need to resort to random variables: Then fine, you made it!
Meanwhile, real scientists are continuing to remove as many of those random variables as they can.

(*and, the only reason things remain random in the Quantum level, is because the Heisenburg Uncertainty Principal has been demonstrated as fundamental to physics as we know it. You have yet to demonstrate that life is fundamentally uncertain, in a similar way.)

 

[andyandy]

How many times can this topic be discussed when everyone knows that each side is just using a different definition of "random" whilst insisting that their own definition is the only one that should be used?

random in common usage and random as understood mathematically are not the same.

American Heritage Dictionary

(1) Having no specific pattern, purpose, or objective: random movements. See Synonyms at chance.
(2) Mathematics & Statistics Of or relating to a type of circumstance or event that is described by a probability distribution.
(3) Of or relating to an event in which all outcomes are equally likely, as in the testing of a blood sample for the presence of a substance.

With definition (1) or (3) you could say that evolution is not random, with definition (2) you could say that it was. Surely posters here have better things to do than pile into another (likely) 300+ post thread based entirely on this semantic point?

(andy bows out of this thread to find something better to do )

 

[mijopaalmc]

Do you even know what those are ?

The fact that you have to ask indicates that you don't know what a straw man is. cyborg's comments are deliberate misrepresentations and supposed reductiones ad absurdum of my arguments. The first one is just a specific example of the argument that my definition of random* "makes everything random", which is a straw man in itself as it is patently untrue. The second uses a description of "deterministic" that makes every system that is based on a set of at least one rule deterministic, which is absurd because it makes random variable deterministic.

*which is implied by the OED's "random distribution, a probability distribution, esp. the Poisson distribution" despite sol invinctus' protestations