Even though I too am very sceptical about this aspect of Darwinian thinking, I don't know if you have characterised the role of 'chance' correctly. I think what is meant by 'chance' is the absence of either a teleological aim, or the guidance of an 'intelligent designer', in the processes of evolution.

I think a rigorous overall statement of that approach is given in Richard Dawkin's book The Blind Watchmaker. In that, he argues that the combination of randomness with cumulative selection, can account for the development of very complex organisms or organs, such as the eye, which appear to be designed, but which is actually understandable solely in terms of a process of increasing complexity evolving from very simple beginnings.

A quotation from the book:

Natural selection, the blind, unconscious, automatic process which Darwin discovered, and which we now know is the explanation for the existence and apparently purposeful form of all life, has no purpose in mind. It has no mind and no mind's eye. It does not plan for the future. It has no vision, no foresight, no sight at all. If it can be said to play the role of watchmaker in nature, it is the blind watchmaker.

I have some reservations about Dawkins' model, or rather, the philosophy behind it, but at the same time, I think that, as far it as goes, it is quite a good depiction of what really is meant by 'chance' or 'randomness' in respect to evolutionary processes.

I believe that the art of husbandry demonstrates to us that physical variations are most likely not the effect of chance. Domesticated plants and animals evolve in ways which are desirable to us, not in ways dictated by chance. If we had to wait for random mutations to produce the desirable changes which have resulted in the many varied domestic species, we would still be waiting. — Meta Under

You're discounting the vast numbers of individuals that are discarded in the process of selecting for an individual with desirable traits, over many generations. Gene modification by mindful selection does take a while as one is growing out plants and or animals which would not otherwise be selected for because of any number of possible chance variables.

In some sense you can pile on the unlikelihood of human husbandry in the universe as a chance event in selecting the Washington Navel clone.

Firstly, of course you're right that selective breeding results in phenotypic changes that are non-random, because which ones survive depends on decisions made by the breeder. But the mutations that result in these changes are random in just the same way as they are in natural selection. Secondly, "survival of the fittest" has not been a popular phrase in Darwinian theory for a long time, partly I think because the notion of survival is misleading in the way you describe, especially when combined with a misleading notion of fitness. But in any case fitness in biology just means reproductive fitness, and what is crucial in the theory is the survival of the traits, not the survival of individuals. Life-span has never been emphasised in the theory in the way you suggest it has. Note also the importance in evolutionary theory of sexual selection, which is precisely about, as you put it, "those physical traits and behaviours which prove to be desirable to a reproductive partner".

Evolutionary biologists agree with you that evolution is not random and is not a matter of chance, but crucially this doesn't entail either that chance has no role in the process, or that there is any purposeful direction of the process.

It might be helpful to discuss what is meant by chance or randomness with regard to evolution, unless it is blatantly obvious of course.

Good idea. I don't think it's blatantly obvious at all. In the context of genetic mutation it means that whether a mutation is beneficial or not does not affect the probability that it will occur. However, it seems that some mutations are more probable than others, so the terms "random" and "chance" can be misleading even when applied in the way that is often thought to be correct.

'Survival of the fittest' was coined by Herbert Spencer, who was the Dawkins of his day (albeit more philosophically savvy IMO). But it is very close in meaning to the principle of natural selection, which, as many have pointed out, tautologically means that 'survivors survive'.

Yes, and Darwin liked the term so much he started using it himself. These days I think it's more apt to mislead.

I agree that the term 'random' can be misleading and is somewhat ambiguous. Is it meant to deny that nature is deterministic? I think jamalrob's definition (that the beneficence of the mutation does not affect its probability of occurring) captures the intention of the model. But does that entail that acquired characteristics and interactions with the environment in general cannot influence the occurrence of mutations? If so, then it might be considered to be a somewhat outdated idea.

I think it is better to restrict the interpretation of 'random' to meaning 'not purposeful' since the posited lack of telos is the cornerstone of Darwinian theory, and in my view its only real innovation, along with the hypothetical model of 'natural selection' that is used to replace telos. In some ways I think something like Lamarck's model, that involves the possibility of the directive influence of acquired characteristics is looking more likely these days due to advances in epigenetics.

I think it's obviously felt to be chance as distinct from design. As Nagel comments in his essay, Evolutionary Naturalism and the Fear of Religion, 'Darwin enabled modern secular culture to heave a great collective sigh of relief by apparently providing a way to eliminate purpose, meaning and design as fundamental features of the world. Instead they have become epiphenomena, entirely explained by the non-teleological laws of physics on the material of which we and our environments are all composed.' That idea of 'having been explained by' is key here; because it means that we ourselves, our identity, is something that is in-principle a matter for science. In an age of outsourced services, what could be better than outsourcing your identity to experts? ;)

Two other factors that it took me a while to grasp are (a) neutral alleles - there are many elements that are simply neutral for fitness, and (b) genetic drift - the ordinary accidental variation in a population that then has effect down the reproductive line.

How keen we are to find purpose on the nature of things!

The notion of "chance" within evolutionary theory is simply a myth. — Metaphysician Undercover

I'd say that the notion of "chance" within evolutionary theory is NOT a myth, but indeed an indication of what is still unknown. (if anything, it is an admission of humility and an indication of limits)

( EDIT:

I have the notion that Wayfarer put it a bit better in stating 'causes yet discovered' than simply stating it as unknown. )

What appears to happen by chance does indeed have determining factors. Problems arise in establishing certainity in that when there are simply too many determining factor or factors we are simply not in the position to take into consideration (those we cannot detect or cannot understand or simply have far too little time to take into consideration due to limitation of our lifespans) we simply look at that particular as being the result of chance. In short... we don't know.

The term in evolutionary theory functions much like the term "luck" funtions in our everyday activities.

Luck is more or less an unanticipated action/event/outcome that indeed does have determinging factors, but we are either unaware of them or simply do not particularly care to make an investigation into why it played out as it has; thus we attribute it to luck.

Chance is an admission of there is more to discover.

Rather than accept the facts of life as real brute facts, the scientific community would rather hide behind the myth of "chance". — Metaphysician Undercover

I'm not really sold that science is rejecting facts, but it's more that science is a continual investigative process of accumulation/adaptation leading to refinement rather than a static point of absolute certainty to on sitting upon dogmatic positions as "real brute facts" that are to be unchallenged.

Chance is an indication that the investigative process remains a process rather than live within a refuge of absolute universal brute facts... which might well be answering the unknown with the unchallengable unknowable that indeed is no answer at all.

Meow!

GREG

Get it! So 'chance' is actually a name for 'causes yet discovered'. I like it.

Jamalrob seems adamant that genetic mutations are, in some sense, random. But if we take as an example, an animal such as the horse, why does an animal such as this continue over time, to change in the same direction? It continued to get bigger and bigger. This is what we find in domestication, once a beneficial direction is determined, an organism will be encouraged to continually evolve in this direction. This characteristic of evolution can be noticed in most plants and animals involved in husbandry. It appears like the creature can be directed in its evolutionary changes. This is not supportive of Darwinian random change, it is more supportive of Lamarckian habituation.

Sure, "modification by mindful selection" takes a while, as Nils Loc indicates. But how much time is necessary for random mutations to cause the changes we observe, as compared to the time over which these changes have actually occurred? It appears to me like domestication causes radical changes over very short periods of time. Look at the many variations of dogs for example.

As Wayfarer says, random genetic mutations "can account for the development of very complex organisms or organs", but the question is whether this is the correct account. The problem with "chance" is that it doesn't decisively rule out anything, so that something which appears to be against the odds could still be ruled as chance. If your neighbour is winning millions in the lottery every five or ten years, he might claim that he is just lucky, but wouldn't you think that something other than chance is going on?

The question of chance is not an issue of whether the likelihood of mutation is affected by its beneficence because this draws us into the question of beneficial for what, diluting the objectivity which we desire. Is it beneficial to an individual's survival, or is it beneficial to reproduction, and therefore beneficial to the survival of the trait, or is it beneficial for something completely different than these two?

The question has to do strictly with the cause of such mutations. Beneficial mutations occur, that is an undeniable fact. What is the cause of them? It is wrong to single out "beneficial to survival", and claim that such mutations appear to be random amongst the multitudes of other mutations, because plants and animals are engaged in multitudes of activities and a particular mutation may be beneficial to any one of these activities, while the activity itself is not necessarily beneficial to survival. Thus the proportion of mutations which are actually beneficial is much higher than those which are "beneficial to survival", because they are beneficial to activities which are not conducive of survival. So when determining the proportion of mutations which are beneficial, we must determine all possible forms of benevolence. This means we have to look at the question in a different way, removing the subjective goal posts of "survival" which we have installed. The question is, is a plant or animal's own behaviour capable of influencing genetic modifications so as to support that behaviour in future generations. That is the point of Lamarckian evolutionary theory. And if this is the case, then words such as "chance" and "random" should be removed from our understanding.

We know that many genetic changes have identifiable causes, so they are not completely random. As John says, to think that "interactions with the environment in general cannot influence the occurrence of mutations" is an outdated idea. So why propagate this myth that mutations are random? If it's the case, as Mayor of Simpleton says, that "chance" just stands in for "unknown", then this is outright deception. To replace "I don't know the cause of X" with "X is a chance occurrence", is to claim that X is known to be a chance occurrence, when the individual making this claim truly believes that the cause of X is unknown.

If your neighbour is winning millions in the lottery every five or ten years, he might claim that he is just lucky, but wouldn't you think that something other than chance is going on? — MU

If your neighbour invest hundreds of thousands of dollars buying lottery tickets, and you buy the occasional one, then her chances are going to be much greater than yours. Chance is still an element in both cases, but it's not the only factor.

Jamalrob seems adamant that genetic mutations are, in some sense, random. But if we take as an example, an animal such as the horse, why does an animal such as this continue over time, to change in the same direction? It continued to get bigger and bigger. This is what we find in domestication, once a beneficial direction is determined, an organism will be encouraged to continually evolve in this direction. This characteristic of evolution can be noticed in most plants and animals involved in husbandry. It appears like the creature can be directed in its evolutionary changes. This is not supportive of Darwinian random change, it is more supportive of Lamarckian habituation — Metaphysician Undercover

"Random change" doesn't mean without cause. It means "without reason." Why is that horses got bigger and bigger? We might say "natural selection" or "directed changes" (and that is, causally, true), but it still leaves the "why" unanswered. How come horses existed rather than not? And how come the existed with pressures which made them bigger (as opposed to anything else)? Why were these particular states necessary as opposed to any other?

"Chance" is to say there is no answer to this question. There is no purpose or logic which made horses and their environment exist like this. It's just what happened. It was arbitrary "chance" that these horses existed, were naturally selected and directed the way they were, as opposed to any of the other countless options which might have occurred-- "chance" is not opposed to the determinism of causality but an expression of it.

I think it's obviously felt to be chance as distinct from design. As Nagel comments in his essay, Evolutionary Naturalism and the Fear of Religion, 'Darwin enabled modern secular culture to heave a great collective sigh of relief by apparently providing a way to eliminate purpose, meaning and design as fundamental features of the world. — Wayfarer

The issue here is not "design" specifically, because design implies some external agent as the designer and cause. What I am addressing is the cause which is within oneself. Do creatures, through their own choice of actions, consequently behaviour, influence the physical traits of their future offspring, as Jean Lamarck assumes? I believe that choice in sexual reproduction is an extension of this principle. Choice in this activity is a valid example of how one's behaviour influences the genetic traits of the offspring.

... as Mayor of Simpleton says, that "chance" just stands in for "unknown", ... — Metaphysician Undercover

Well...

I have the notion that Wayfarer put it a bit better in stating 'causes yet discovered' than simply stating it as unknown. (not to mention that Wayfarer sort of liked something I said... hasn't really happened all too often; thus I must have accidentially said something that might have a tiny bit of merit... poker tells in philosophy)

Anyway (for what it's worth here)...

One thing I usually consider is that evolutionary theory isn't termed evolutionary law. I feel that this reflect the difference between scientific theory and scientific law.

To my knowledge, scientific laws differ from scientific theories (or hypotheses) in that laws do not posit a mechanism or explanation of phenomena. A scientific law always applies under the same conditions and implies that there is a causal relationship involving its elements, thus they are merely distillations of the results of repeated observation.

In any event scientific laws, as with theories and hypotheses, can indeed make predictions, but can be falsified if they are found in contradiction with new data accumulated.

Perhaps if someone would suggest that "chance" is a force of nature or a guiding hand or a metaphysical construct in the manner that luck is thought of by some (especially gamblers or the superstitious), then we might have a beef that chance is a form of deception.

I still find that chance is a check to any and all scientific theory, especially when one is compelled to view theory as the notion of absolute/universal/static certainty; thus chance is a fuel to the fire of investigative process rather than a bucket of water to extinguish this flame.

Meow!

GREG

@Metaphysician Undercover
The only thing deficient, is you knowledge of evolutionary theory. Had you taken the time to read Darwin's work, you would have seen that what you call "husbandry" is fully covered under the chapters about "Domestic Selection", and was by the reflection on these matters that natural selection came about.

I don't agree Mayor.
When it is believed that there is a cause or reason for a particular occurrence, the cause or reason being unknown, yet the believer claims "chance" for this occurrence, this claim is deceptive. It is deceptive because what is claimed, "chance" is inconsistent with what is believed, "cause, or reason". When an individual claims "X is the case" while believing X is not the case, this is deception. There is no place for such deception in science.

The issue here is not "design" specifically, because design implies some external agent as the designer and cause. What I am addressing is the cause which is within oneself. Do creatures, through their own choice of actions, consequently behaviour, influence the physical traits of their future offspring, as Jean Lamarck assumes? I believe that choice in sexual reproduction is an extension of this principle. Choice in this activity is a valid example of how one's behaviour influences the genetic traits of the offspring. — Metaphysician Undercover

Lamarck (and Darwin by the way) assumed that traits acquired by parents were transmitted to their young. Epigenetics aside, we know that isn't true. But of course genetically determined successful behaviours and preferences are selected for, and sometimes, when preferences are the main selection pressure you get peacocks etc.

I think there has been recent research that demonstrates that for a large number of species, males are subject to immense selection effects by females. Of course in all non-human animals, it is the genes of females who have chanced upon the right selection criteria that propagate. The behaviour of the females being genetically determined.

Under neo-Darwinism, the requirement is that there is no systematic mechanism of variation. That is all "chance" and "randomness" mean in this case. In fact sexual reproduction is a mechanism of introducing non-systematic variation.

For your information charleton, I have read a substantial amount of Darwin's work, as I have of Lamarck's. Notice in the op, that I indicate the designation of "chance", or "random mutation" comes from modern theorists, not Darwin himself. I believe Darwin was more careful just to identify objectively, the scientific reality of such variations, without needing to assign a cause of them.

Lamarck (and Darwin by the way) assumed that traits acquired by parents were transmitted to their young. Epigenetics aside, we know that isn't true. — tom

Epigenetics aside? You mean, the rule holds as long as we put aside the vast quantity of evidence which goes against the rule. OK, so "that isn't true", so long as we ignore the overwhelming evidence that it is true. That doesn't make sense to me, does it make sense to you?

Epigenetics aside? You mean, the rule holds as long as we put aside the vast quantity of evidence which goes against the rule. OK, so "that isn't true", so long as we ignore the overwhelming evidence that it is true. That doesn't make sense to me, does it make sense to you? — Metaphysician Undercover

Epigenetics aside, because there is a huge amount of confusion and misunderstanding associated with it. Neo-Darwinism may indeed have evolved a mechanism by which certain changes to offspring are brought about as a temporary measure for a generation or two.

I don't agree Mayor. — Metaphysician Undercover

Fine...

When it is believed that there is a cause or reason for a particular occurrence, the cause or reason being unknown, yet the believer claims "chance" for this occurrence, this claim is deceptive. — Metaphysician Undercover

The claim is not deceptive, the claim is ignorant.

The claim is only deceptive when one wishes to claim chance as a "natural force" or an "agent of cause".

Also... please note... you called chance "unknown". I didn't call it that, so in a way this position you have thrush upon me is well... deceptive.

It is deceptive because what is claimed, "chance" is inconsistent with what is believed, "cause, or reason". — Metaphysician Undercover

Not sure what to make of that...

... I still view chance as more an result that can be known if one can make an investigation in to all the determing variables, but one either does not or cannot make this investigation.

In any scientific investigation there are degrees of freedom involved. There are factors that one does not and indeed cannot take into consideration. In spite of the deficit one can still know some things with a reasonable degree of certainty.

Here might be the problem. By calling chance the "unknown" it seems as if there has been an assumption that what is here unknown is indeed unknowable. I really cannot agree with that, nor is what I would suggest.

Another point to make here would be regarding standards of measure.

At what point is something considered to be reliable?

At what point is there enough investigation to indicate that something may very well be a cause or a reason beyond any reasonable doubts?

When an individual claims "X is the case" while believing X is not the case, this is deception. There is no place for such deception in science. — Metaphysician Undercover

Here we can agree. There is no place in science for this sort of deception, but I don't think it is very often the case in scientific investigation.

Such a deception as you mention is very rampant in other non-scientific pursuits... often in the fields of religion, metaphysics and politics... fields where they have a great tendency to use non-scientific approachs to forming a worldview, in that they start first with the answer and then work toward forming a universe of questions where the pre-assumed answer remains unchallenged.

I can remember a member of PF (psychotick I believe) who refered to this as "top-down thinking". (...as if science was "bottom-up thinking". Personally I feel science has no top or bottom, but rather expands in a multitude of directions without a pre-assumed directionality as a bias.)

Anyway...

... I can't really say I agree with you here, nor was I the one who stated "chance" is unknown.

Meow!

GREG

I'd say that the notion of "chance" within evolutionary theory is NOT a myth, but indeed an indication of what is still unknown. (if anything, it is an admission of humility and an indication of limits) — Mayor of Simpleton

I'd say that the notion of "chance" within evolutionary theory is NOT a myth, but indeed an indication of what is still unknown. (if anything, it is an admission of humility and an indication of limits) — Mayor of Simpleton

Well...

I have the notion that Wayfarer put it a bit better in stating 'causes yet discovered' than simply stating it as unknown. — Mayor of Simpleton

Indeed...

... proof that postions can refine.

Meow!

GREG

Indeed...

... proof that postions can refine.

Meow! — Mayor of Simpleton

Neo-Darwinism requires the mechanism of variation to be non-systematic. So, no there can be no "causes yet undiscovered" only particular historical accidents.

That's cool, but I was refering to my statement. (which I suppose needs more refinement)

Indeed I did start out with "unknown", but refined that to something far less misleading. (or so I thought)

I'm not too sure how Neo-Darwinism resulted in my changing the notion, as I feel it had more to do with Wayfarer's reply..and knowing the relationship I've had with Wayfarer that deserves a WOW! ;)

Meow!

GREG

@Tom
" males are subject to immense selection effects by females."
Indeed, and the main case often used to express Lamarkian evolution; the length of giraffe necks has little or nothing to do with reaching for the leave of trees. In fact giraffes mainly and very uncomfortably graze grass from the ground. The reason they have such absurdly long necks is the fact that males engage in fierce competition for females by using their heads as war hammers and throw themselves against other males with their long necks.
Sadly, like males have nipple, both males and females are burdened with this absurd adaptation and struggle to get blood pressure enough for their brains, and have to contort themselves to eat, from the ground.