Evolution quotes: Quetelet on populations

by John S. Wilkins | January 22, 2012

Dark days

Wikipedia dark In case you didn’t notice, just recently a number of web giants, as well as innumerable other websites, went “dark” in protest against the attempts to control the internet by the US government. But the US isn’t the first nation to attempt this. Iran, Turkey, India, China, and to the eternal shame of all Australians, my own nation, have set up, or plan to set up, controls over the internet.

Some of this is part of the encroaching copyright hegemony of Hollywood, and the music industry, or religious and moral concerns. However, the bulk of it is due to a single, simple, fact: governments and their bureaucracies like to acquire control, and once they have it, will not give it up without a fight. Over time, the once-free internet (funded by the US Department of Defence initially) has become hedged in with legal obligations for ISPs and website hoisters that no telephone company or postal service would have endured. Now, the default opinion is that if somebody may use your service to do something illegal, it is no longer the responsibility of the police and courts to find, punish and stop these crimes. It is not the responsibility of the companies and individuals who are thus exploited.

Once upon a time, punishment followed the crime, and the people who committed the criminal acts were held to account. Now, punishment not only can precede the crime, but individuals who happen to be inadvertently involved can also be punished, even if, and this seems to me to undercut the very existence of our code of law, they had no way to prevent themselves being involved in the criminal act!

So if someone happens to use my car for a crime, I can be punished by having my car confiscated, without any proof I was involved or knew of the crime ahead of time, and without any charges being laid and tested in court. This principle of pre-emptive punishment is more than draconian, it is Kafkaesque. It makes no sense, legally. The only justification for it has to be that it means statutory instruments of government can control the situation as they wish, without either having to do due diligence of investigation and evidence gathering, or testing their claims in open court.

We are living, I am afraid to say, in the dawn of the world of totalitarianism. It has been coming for a while. Recently I had occasion to re-read the opening chapter of Herbert Marcuse’s One Dimensional Man, first published in 1964. He was thought by most people at the time to be a red rag communist (and he was certainly a Marxist in that philosophical manner of academics) and so he was ignored by the establishment and féted, to his bemusement, by the radical left of the late 1960s. When I read him, I was put off by the Hegelian language and the fact that he was a “leftist”, but it seems to me that while his prescriptions might be unworkable (if he actually presented any), his analysis was spot on. The opening paragraphs lay it out:

A comfortable, smooth, reasonable, democratic unfreedom prevails in advanced industrial civilization, a token of technical progress. Indeed, what could be more rational than the suppression of individuality in the mechanization of socially necessary but painful performances; the concentration of individual enterprises in more effective, more productive corporations; the regulation of free competition among unequally equipped economic subjects; the curtailment of prerogatives and national sovereignties which impede the international organization of resources.

That this technological order also involves a political and intellectual coordination may be a regrettable and yet promising development. The rights and liberties which were such vital factors in the origins and earlier stages of industrial society yield to a higher stage of this society: they are losing their traditional rationale and content. Freedom of thought, speech, and conscience were – just as free enterprise, which they served to promote and protect – essentially critical ideas, designed to replace an obsolescent material and intellectual culture by a more productive and rational one. Once institutionalized, these rights and liberties shared the fate of the society of which they had become an integral part. The achievement cancels the premises.

To the degree to which freedom from want, the concrete substance of all freedom, is becoming a real possibility, the liberties which pertain to a state of lower productivity are losing their former content. Independence of thought, autonomy, and the right to political opposition are being deprived of their basic critical function in a society which seems increasing!y capable of satisfying the needs of the individuals through the way in which it is organised. [p1]

I could quote much more, but it is clear that Marcuse, along with other critics of the post-war consumer society, recognised that freedom was only permitted so long as it served economic and political needs; when those needs evaporated, the freedoms would also evaporate. And so we see this happening now. The core function of the internet, and indeed all communications technologies today, is to serve “the economy”. Buy and sell on the internet by all means, but do not express yourself outside permitted boundaries.

The encroachment of copyright on older materials that once served to fuel cultural development is a case in point. What is gained by applying copyright protection to works from the pre-war period? Why can’t I put a Mickey Mouse image from the 1920s on my blog without paying a corporation that has way too much wealth as it stands? It is like a large part of my culture, youth and upbringing are censored already. But if the author has died, the investment to that author has been ruled off; and those who benefit are now corporate entities like companies, governments and other institutions.

The control over communication is a crucial element of a totalitarian control by governments, and even when a government is not yet, or likely to be in the future, totalitarian, it can still have unwarrantable control over the lives of people. Given the ratchet effect of gaining but never giving up control over people that governments are subjected to, we should fight hard to both prevent them getting more control, even when it seems like it is necessary, and to remove controls for which there are no good reasons apart from tradition. And in all cases, we should make sure that the claims of those with controlling powers are tested out in the open at every stage.

This means no more closed court cases, orders and laws forbidding people to even let their families and lawyers know they have been charged. It means that we must be free to communicate even when others may think it wrong or leading to a crime. Until a crime has been committed, nobody has a right to block communications. And even then, blocking them must be done out in the open.

When a totalitarian government like the Stalinism of the Soviets or the North Koreans takes hold, people share information in secret, in Samizdat. Governments hate this form of communication and will do everything they can to impede it; this is what we are seeing in the west and developing nations now. Other ways to impede communication include the time honoured technique of making certain kinds of speech defamatory and putting the onus not on those who would claim to have been defamed to prove it, but on those who speak to prove they are not. This has the effect of making free speech only available to those with the money and lawyers to pursue such actions, while it chills everybody else. Copyright and corporate protections like SOPA and PIPA have the same effect. I now can’t quote somebody in a publication for academic publishing, even in the light of “fair use” provisions, without written permission and payment of fees, as I have discovered in several cases. If you think that doesn’t chill my speech, you don’t understand how it all works.

It can only be a matter of time before the Wayback Machine at archive.org is served with copyright violations for mirroring what people put out in public. Instead of serving claims against those who first made the material public (often the very people now claiming the violation against them), it is so much easier, and serves so many corporate (that is, commercial, government and institutional) interests, to attack the host service. This has an added bonus of allowing people to control what they are seen to be doing. In the old days, you could go check a newspaper or printed pamphlet in a library; now you can’t. We can rewrite historical evidence at last…

We are in the endarkenment. Where once we thought information would lead us to truth, we now fear that in fact it might just do that, and truth is no longer what we, or our masters who tell us what we must value, desire. We instead have a comfortable unfreedom. Dark days indeed.

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Filed under Freedom, Politics, Rant, Sermon

by John S. Wilkins | January 21, 2012

A philosophical apology from 1919 for not being pro-war

Leiter posted the PDF of this on his site. I can’t help but reproduce some of the choicer quotes:

“DEAR FRIEND: Your letter gently but un-mistakably intimates that I am a slacker, a slacker in peace as well as in war; that when the World war was raging bitterly I dawdled my time with subjects like symbolic logic, and that now when the issues of reconstructing a bleeding world demand the efforts of all who care for the future of the human race, I am shirking my responsibility and wasting my time with Plato and Cicero. Your sweetly veiled charge is true, but I do not feel ashamed of it. On the contrary, when I look upon my professional colleagues who enlisted their philosophies in the war, who added their shrill voices to the roar of the cannons and their little drops of venom to the torrents of national hatreds, I feel that it is they who should write apologies for their course. For philosophers, I take it, are ordained as priests to keep alive the sacred fires in the altar of impartial truth, and I have but faithfully endeavored to keep my oath of office as well as the circumstances would permit.

…

I believe in the division of labor. I am a priest or philosopher, not a soldier or propagandist. I yield to none in my admiration for the brave fellows who gave their all on the bloody fields of Flanders, but I have no respect for the bigots who cannot realize that “there are many mansions in my Father’s house,” and that it would be a poor world if there were no diversity of function to suit the diversity of natural aptitudes. And when people begin to admonish me that if everyone did as I did, etc., I answer that humanity would probably perish from cold if everyone produced food, and would certainly starve if everyone made clothes or built houses. I admit the desperate need of men to defend the existence of our country, but I cannot ignore the need of men to maintain even in war the things which make the country worth defending. Purely theoretic studies seem to me to be of those fine flowers which relieve the drabness of our existence and help to make the human scene worth while.

…

If I had your persuasive talent, dear friend, and cared to exalt one human interest above others, I would contend that the really important issue before the American people today is not economic or political but moral and vital—the issue of Puritanism. It is the Puritanic feeling of responsibility which has blighted our art and philosophy and has made us as a people unskilled in the art of enjoying life.

…

The great philosophers, like the great artists, scientists and religious teachers have all, in large measure, ignored their contemporary social problems. Aristotle, Leonardo da Vinci, Shakespeare, Newton, Buddha, Jesus of Nazareth and others who have done so much to heighten the quality of human life, have very little to say about the actual international, economic and political readjustments which were as pressing in their day as in ours. The great service of Socrates to humanity was surely not in his somewhat superficial criticism of the Athenian electoral machinery of his day, but rather in developing certain intellectual methods, and suggesting to Plato certain doctrines as to the nature of the soul and ideas,—doctrines which in spite of all their impracticality have served for over two thousand years to raise men above the grovelling, clawing existence in which so much of our life is sunk.”

From the New Republic, December 5, 1919. As such it is now out of copyright, despite what TNR says.

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Filed under History, Logic and philosophy, Philosophy, Politics, Quotes, Sermon, Social evolution, Truisms

by John S. Wilkins | January 21, 2012

A logical inference, or, on how to submit Carnival of Evolution posts

I could put this into standard logical form, or even argument map it, but I’m too lazy. However, since I’ll be hosting one of these soon, I should post this the way Bjørn Østman sent it to me:

Carnival of Evolution only works if people submit posts.
A person can only submit posts when they know they exist.
The first person to know about the existence of a post is the author.
When you write a blog post about evolution, submit it right away right here.
The first person to know about the existence of a post is the author.
A person can only submit posts when they know they exist.
Carnival of Evolution only works if people submit posts.

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Filed under Administrative, Evolution

by John S. Wilkins | January 18, 2012

The Shandyan dilemma

Reginald Hill, author of the Dalziel and Pascoe detective series among many others, has died. This is a partial post I started some time back, so I thought I’d post it as is.

In Recalled to Life, Reginald Hill has one of his two protagonists, Pascoe, interview an ex-nanny who is cleared of murder after 30 years in prison.

Pascoe … had anticipated a frosty welcome from the ex-nanny but instead found himself drinking Earl Grey and listening to nursery reminiscences which stretch forever like childhood summers. At one point without interrupting her flow she had arisen, gone over to an ornate escritoire which looked like it would fetch a bob or two at Southeby’s, and taken from a drawer a well-filled photograph album. Thereafter her lecture was illustrated, and for the first time Pascoe truly appreciated the Shandyan[1] dilemma that present becomes past at a rate faster than past can be retrieved into the present. [p83]

The aphorism is not in Tristam Shandy itself, so far as I can tell, but it refers to the curious structure of that classic novel, in which the attempt to give an autobiography has to take so many detours through the past before the eponymous author’s birth that it never actually manages to do much by way of autobiographising.

In my species book, I wrote this:

Generally, scientists have a “rolling wall of fog” that trails behind them at various distances for different disciplines, above which only the peaks of mountains of the Greats can be seen. In medical biology, for instance, this wall is about five years behind the present. Little is cited before that, and those works that are, are cited by nearly everyone. So there is a tendency for what Kuhn called “textbook history” to become the common property of all members of the discipline. [p ix]

Generally what happened in the past is something that slowly disappears as evidence and recollections fade or become fixed into clear and distinct narratives. An example is David Hull’s book Science as a Process, which (among many other things) gives the narrative of the birth of cladistics (phylogenetic systematics). I have spoken to several of the key players, from different sides of the debate. One thing they all agree on is that Hull got the events wrong. What they all disagree on is what he got wrong.

History of science – indeed all history – is like a traffic accident. Every witness remembers things differently, and so the process of doing the history of science is a matter of taking more or less objective facts – usually documentary evidence – and trying to construct a narrative free of the individual narratives reconstructed by the actors and those who have loyalties or hatreds for the actors. But textbook history is hard to overcome. As Dennis Des Chene notes at the excellent philosophy blog NewAPPS:

The philosophy of science directs its attention mostly to successful science—to Darwin, not to Lamarck or Driesch—and even when it turns to theories that have proved false, it tends to study only the “honorable” failures. It avoids the Helmonts and Fouriers, the Fechners and Josephsons—those who have sinned (or so it thinks) against reason, and given too free a rein to imagination. After all, if your aim is to understand how reason works, how knowledge is most efficiently attained, you will want the best specimens; the ill-formed, the dubious, the fake, you leave aside.

Why is history so hard to do? Why do we construct these narratives from partial data? In science (and I firmly believe history is a science, not an art, except in the sense that all sciences are art as well) this would be confirmation bias and subjectivity; why not in history?

Well it is, at least in the theoretical sense taught in many history classes (but not all – I leave to one side the so-called postmodern approach to history in which narratives are constructed from whole cloth). We call this sort of interpretation of data to fit a narrative the Whig Interpretation, or presentism, or progressivism.

Add to this that it takes longer to relate the narrative than the events related actually took to occur if there is any degree of depth (the Shandyan dilemma) and the fact that even this depends on what information is available, and history becomes a very hard thing to do, let alone justify.

Consider this: to find out a fact, one has to go digging, metaphorically or literally, through archives, books, artefacts and interviews. This takes time. There is some kind of relation between the age of the fact, and the time it takes to find and verify the fact. The older the event, the longer it takes to find the fact and the greater the likelihood that history has erased the facts by overwriting, deleting and modifying the evidence.

A friend, who is a medievalist (and physicist) wrote:

Consider the Battle of Hastings. We have six (or was it eight) more or less contemporary sources for the battle. They agree that the battle started around 9 in the morning. And they agree that Harold lost.

They disagree on everything else.

In spite of six (or was it eight) more or less contemporary (and detailed) sources, we may never know what happened at Hastings.

It’s not that we lack evidence. It’s that the evidence is not constraining possible past states. And as history marches on, all we can do is narrow down the past states from an unmanageable number to a hopefully manageable number. We know Caesar never crossed the Amazon. We know he crossed the Rubicon. Why, how, exactly when, with exactly how many soldiers, and so forth, may be lost to us. What he ate that morning is certainly lost to us.

I continued in my book:

Doing this kind of history is rather like trying to work out the past from a series of old photographs in a box in the attic you got from your grandparents. Faces appear in various guises, resemblances recur, and it is almost impossible to identify exactly who is whose child, friend or mere passers-by. Nevertheless, having that box of snapshots, one is richer for it in understanding both the past and the present.

The history of science is so often triumphalist, presentist and Whiggist that it displays a major failure to appreciate the Shandyan dilemma. Copernicus, Einstein and Darwin are treated as necessary waypoints on the ineluctable path to our present science so often that philosophers, freethinkers and erstwhile skeptics sometimes act as if it is only a matter of time that rationality is universal and religion and superstition abandoned, as if species developed and matured the way individual organisms are sometimes held to. But information is lost over time, so advances will reach a point at which the transmission of them to the future balances the information lost, and so there may be a point at which the Shandyan dilemma leaves us unable to progress any farther.

[1] Some editions (I think the American) have “Shandean”. I wonder which was original?

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Filed under Evolution, History, Philosophy, Social evolution

by John S. Wilkins | January 15, 2012

Notes on Novelty 8: Conclusion – Post evo-devo

Notes on Novelty series:
1. Introduction
2. Historical considerations – before and after evolution
3: The meaning of evolutionary novelty
4: Examples – the beetle’s horns and the turtle’s shell
5: Evolutionary radiations and individuation
6: Levels of description
7: Surprise!
8: Conclusion – Post evo-devo

With the growth of developmental genetics, it is possible to see beyond the view of homologies working at the level of whole organs. The mechanisms that define the ordinate axes of structures, the genetic circuits that pattern them, and the cell types with which organs are formed can be considered. The more that researchers look, the more they will find that the same tools have been used to build a great variety of structures long thought to have independent histories. Discerning what has been conserved and what is novel in the origins of organs and body plans will be possible only with more comparative data, experiments on non-model animals, and targeted fossil discoveries from crucial nodes in the tree of life. (Shubin et al. 2009: 822)

My conclusion is that we find novelty in a subjective sense, based upon what we think we should find in the data. Further knowledge of the underlying or overlaying mechanisms should reduce the surprisal of the trait appearing either in the paleontological record or in a distinct taxonomic group. Only when it doesn’t and in cases where it should, should we start to seek non-Darwinian mechanisms. Much of the debate over novelty in evolution has centred implicitly around what the researchers themselves find interesting, surprising or contrary to the conventional interpretations. Another factor lies in a topic I haven’t discussed here: what counts as “suitably dissimilar”, so a few words on this.

Similarity and its converse, dissimilarity, is often applied to the issues of novelty. Stephen Jay Gould attempted, for example, to apply it in the case of the Cambrian explosion (1990); some fossils’ bodyplans were too dissimilar (using the consistency index of cladistic analyses, C) to put them into existing taxonomic categories (“phyla”); subsequent work did precisely that (Briggs and Fortey 2005). Relying upon morphology – that is, description at a certain grain (indeed, the only grain available to palaeontologists most of the time; cytological data is rare and molecular data nonexistent) – Gould found some traits and overall phenotypes too weird to fit into our classifications. Briggs and Fortey showed over several decades of work summarised in their paper that they could be seen as instances of stem groups of our present clade-based phyla (that is, phyla that have been made monophyletic).

What is similarity in taxonomy? It is true that rarely does this get any kind of analytic or quantitative analysis, especially in palaeontology, but that doesn’t mean there is no analysis underlying it of which the authors are not conscious (or think it too obvious to state). The best analysis of the recognition of similarity in the literature is that of Amos Tversky, who argued that the similarity of one thing to another is the overlap of features minus the unique features to each object, out of a “feature set” (1978). This is now called “Tversky Similarity”:

[TS]

What is crucial to understanding similarity like this, which was developed for a generic psychological account and not just for science, is that the choice of features to evaluate (which may be entirely unconscious, or a cultural convention, or even biologically imposed) determines what counts as similarity in each case. With a different feature set, different similarity indices might arise, and indeed the history of science has been one of finding the “right” feature set (for example, in the case of elements and the periodic table, Scerri 2008).

The alternative to using apparent similarity, especially at a given grain of description (the gross morphology of the organism) is to use homology. Instead of treating the relations between organisms and specimens as a matter of what they “look like”, identify homologs and organise your groupings on that basis – this is the reason for cladistics. Homologies, not similarities in the eyes of the beholders, set up a baseline for assessing how novel a trait may be, and if we can find the developmental, physiological, molecular and environmental reasons for the novelties thus uncovered, so much the better. All I am criticising is the idea that somehow, in ways we can’t even properly articulate, we need to “go beyond” or “extend” the Darwinian approach. In one sense of course we do; Darwin did not know everything. In this case, we do not; Darwin has been validated again and again regarding novelty.

I am not dismissing the idea that there can be an evolutionary explosion from some novelty or node in an evolutionary tree, although these are more often the result of subjective assessments (the Cambrian explosion has, for example, become less and less of an explosion and more and more of an evolutionary diversification of the ordinary kind, as paleontological evidence has come in). What I am dismissing is the notion that there is some objective sense in which evolutionary novelties are natural kinds. Radiations occur all the time – some clades are speciose and others are sparse. If there is a general principle why this occurs, it is not yet obvious. Maybe some kinds of developmental modularities do cause clades to be more radiative. Maybe, however, is not an explanation.

Science progresses best when it eliminates subjectivity from its categories; anthropomorphism has ever been the bugbear of good science (unless anthropoi are the objects of study, and even there we tend to project ourselves on our subjects, as any anthropologist can tell you). It has taken us over a century to begin to recognise that what Darwin started requires this in biology as in the other physical sciences. So I would like to leave the last word to somebody of a certain weight in evolutionary biology, and who seems to be on the right side of the debate on many issues, Sewall Wright:

“Creative” and “emergent” evolution

The present discussion has dealt with the problem of evolution as one depending wholly on mechanism and chance. In recent years, there has been some tendency to revert to more or less mystical conceptions revolving about such phrases as “emergent evolution” and “creative evolution.” The writer must confess to a certain sympathy with such viewpoints philosophically but feels that they can have no place in an attempt at scientific analysis of the problem. One may recognize that the only reality directly experienced is that of mind, including choice, that mechanism is merely a term for regular behavior, and that there can be no ultimate explanation in terms of mechanism—merely an analytic description. Such a description, however, is the essential task of science and because of these very considerations, objective and subjective terms cannot be used in the same description without danger of something like 100 percent duplication. Whatever incompleteness is involved in scientific analysis applies to the simplest problems of mechanics as well as to evolution. It is present in most aggravated form, perhaps, in the development and behavior of individual organisms, but even here there seems to be no necessary limit (short of quantum phenomena) to the extent to which mechanistic analysis may be carried. An organism appears to be a system, linked up in such a way, through chains of trigger mechanisms, that a high degree of freedom of behavior as a whole merely requires departures from regularity of behavior among the ultimate parts, of the order of infinitesimals raised to powers as high as the lengths of the above chains. This view implies considerable limitations in the synthetic phases of science, but in any case it seems to have reached the point of demonstration in the field of quantum physics that prediction can be expressed only in terms of probabilities, decreasing with the period of time. As to evolution, its entities, species and ecologic systems, are much less closely knit than individual organisms. One may conceive of the process as involving freedom, most readily traceable in the factor called here individual adaptability. This, however, is a subjective interpretation and can have no place in the objective scientific analysis of the problem. [Wright 1931: 159]

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Filed under Epistemology, Evolution, General Science, Logic and philosophy, Metaphysics, Natural Classification, Philosophy, Science, Species and systematics, Truisms

by John S. Wilkins | January 14, 2012

Notes on novelty 7: Surprise!

It is now time to return to the basic argument of this series. You will recall that it went like this:

1. Novelty is specified at some level of description based on there being a nonhomologous structure or function
2. There is always some level of description at which there is a homology for the underlying developmental or hereditary mechanisms that develop the novel trait
3. Novelty is therefore a function of the level or scale of description
4. What makes it novel is therefore our lack of knowledge of the right scale or level of description of traits; when we learn the right level (say, protein or cytological), the novelty seems less novel or not novel at all.
5. Novelty is therefore a matter of the surprisal value of the trait relative to homologies at that scale

I have made out premises one to four. Now it is time to argue for the conclusion.

There is a concept in information theory known as the surprisal value of a received message: basically it is that the information content of a message is the degree to which the sequence is surprising, which is to say, the inverse of the expectation that the sequence would be received by chance:

where the probability p is 0 ? p ? 1. This is also called “self-information”. Note that the key term here is expectation. The point of surprisal is that it relies upon our prior expectations of probabilities. To the extent that we have an estimation of those distributions of probabilities, the received message is surprising and informative.

An analogous case is in play here. We describe (that is, set up a sequence of symbols, either in verbal or mathematical form) some traits or characters in biological cases and estimate their likelihood under “ordinary” evolution or drift. We then are surprised (informed) when the traits concerned do not fall out as likely. This, we think, calls for a special explanation and so we start looking at “non-Darwinian” causes.

Let us consider what “Darwinian” causes might be. Darwin adduced several causes of evolution: natural selection, sexual selection, artificial selection, use and disuse, and correlation. We can lump all the selective processes together under the rubric “selection”, as all that divides them is the intent of the selective agency, or a lack of it. Use and disuse was what is often misleadingly called Darwin’s “Lamarckism”, but I have argued before that it was not. He merely thought that traits that were useful would be more strongly inherited and those that were not would be weakly inherited. As a source of novelty, use and disuse is otiose. He did not think this was a case of acquired characters as such. In any case we can dismiss this, pace epigenetics, as a case of evolutionary novelty on the basis of modern knowledge. Correlation is now known under the rubric of allometry. Some traits (like large antlers) can be due simply to regulation and moderation of growth – if body size is upregulated, antlers will grow disproportionally due to differential growth rates of parts. That leaves selection as a Darwinian mechanism for novelty. Indeed, it leaves selection as the sole mechanism for novelty.

Objections to selective accounts of novelty often rely on the argument that selection only determines the subsequent fate of a novel trait (i.e., whether it spreads to fixation or equilibrium, or is eliminated), not its origin, and there is a sense in which this is true, but we should not be so restrictive about what selection includes. Darwin and Wallace always held that selection involves prior variation; which we now refer to as mutation since the Mendelian revolution. In any sensible interpretation, selection involves random mutation (random, that is, to the selective value of the traits in that population in that environment, or any future population and environment linearly derived from it).

Another class of objections to selective accounts of novelty is that selection must occur gradually, with fitness improvement at every step. Some of these novelties are thought not to have such intermediate improvements in fitness gradients. In the case of our two exemplars, the turtle shell and the beetles’ horns, this is not the case; we can see fitness improvements (the turtles being ecological, and the beetles being sexual) at every stage. We can leave this case to one side here, then.

So taking selection to be blind variation and selective retention, in Donald Campbell’s felicitous phrasing (Campbell 1965), the mechanism that produces novelty in a Darwinian fashion is some random variation to an existing trait, and selection on it when it has fitness differences. Obvious enough. However, it needs a bit of filling out. Fortunately, Thornhill and Ussery have done this already (2000). The pathways or routes to novel traits posited by the most general Darwinian view, and I think properly assigned to Darwin himself, are: serial direct evolution, parallel direct evolution, elimination of functional redundancy, and adoption from a different function. I will paraphrase and extend these (which were originally written to deal with the rather uninteresting claims of intelligent design).

Serial direct evolution occurs when some trait is modified along the lineage (the ancestor-descendent sequence), so that the trait at the end is distinct from the trait at the beginning. The sequence in seriatim has to occur at what I am calling the same grain of description. Changing the grain (upwardly or downwardly) would no long count as a series. I would call this sequential evolution of novelty.

Parallel direct evolution occurs when more than one functionally connected component is modified simultaneously to form a complex structure. The example Thornhill and Ussery give is a table where all the legs need to be extended in concert for the table to function (and the biological example here is the complex vertebrate eye). This is clearly compositional in nature.

How parallel and serial evolution can actually differ, as opposed to being merely conceptually different, is unclear. Any trait in a living system, because it is a system, must involve more than one part. Suppose a serial evolutionary process modifies a rib. That will change all attachments and integuments connected to the rib. It will change the shape of the body, and hence the locomotory subsystems. Internal organs and functions will shift, subtly or greatly. Organisms are not evolved by adding a single new part, and given that organisms develop as a system, any change in any part will affect many others, which will have to evolutionary adjust over time.

So I think that we can bring these two forms of Darwinian evolutionary routes into one: some part or parts are modified lineally and in sequence. This is not necessarily gradualism, though. Changes at one grain of resolution and description can be abrupt, so long as the descriptions at some grain allow us to identify homology over time. [A change without homological relations would indeed be non-Darwinian.]

The elimination of functional redundancy occurs when a part that had a now-redundant or unnecessary function loses that function enabling it to form the seed for another function. This leads to adoption from another function. Functional descriptions, however, are relative to the choice of functions that matter to the observer; it is inevitable that a part of almost any function of any complexity will also play a functional role in several or many other functional processes. So while the bones of the jaw that became those of the middle ear (Thornhill and Ussery’s example) lost their functional role as “jaw bones” (as stress-supporting biomechanics structs for mastication), they undoubtedly retained their functional role as skull supporting, facial muscles supporting bones, while they evolved. They “lost” one function (or better, lowered it gradually, more or less) and gained another “gradually, more or less) but retained many others and these, too, evolved. Our choice of what to describe here remains the key issue. Again, also, I think we can collapse these two.

Darwinian selection occurs on variation, so the real question is how variation occurs. As far as I can tell, there are four ways this can happen:

Deletion of a part.
Duplication of a part.
Rearrangement of a part.
Insertion of a part.

Consider genes in the traditional four letter code. A letter can be deleted, given a “novel” sequence (especially if the deletion is in the start or stop region of an open reading frame), or a sequence or letter can be duplicated to the same effect. When duplication occurs, one copy can be retained under the old function, while the new copy evolves through the other three ordinary Darwinian processes. A sequence can be inverted or chopped up and distributed through other sequences, forming all kinds of novelties of products downstream. Or a sequence can have an atomistic part (a “mer”) at that grain of description (here: the nucleotide “letters”) inserted.

Once these novel variants occur, and they may occur through deterministic processes at the grain of description but remain “random” relative to the selective pressures that obtain at the trait or organismic level, selection takes over and explains why so many of the population, or all of them, have the trait concerned.

In no way is an explanation other than a Darwinian selective account required to explain novelty unless it could be shown that a part arose without any kind of precursors whatsoever. In other words, there is no prior sequence of parts at any grain. When arguments are put that Darwinian selection is insufficient to account for a novel trait, usually on the basis of some kind of systems theory, it is because the descriptions do not permit a change of grain. And this is a matter of surprisal only when grain is fixed. Suppose, to return to our information theoretic example, you had a full description of all parts of the sender, and what is fed into it, along with a full description of the channel and the receiver. What might be surprising then would be some noisy interference, not that you had received the same or very similar sequence as was sent. What matters is what your grain of description is – an engineer’s or an operator’s.

It may be that there are indeed properties of systems that are surprising (at least, until we have worked them out) and which have, at some grain of description, explanatory weight in evolutionary contexts; but I suspect and hold that, like selection itself, these will always be promissory notes for a full and physical description to come, just like a mathematical equation is not explanatory until we can fill out the denotation and interpretation of the variables.

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8 Comments

Filed under Cognition, Epistemology, Evolution, Logic and philosophy, Metaphysics, Philosophy, Science

by John S. Wilkins | January 13, 2012

Size matters

As always, click on the image to go see the entire Tony Piro goodness

2 Comments

Filed under Evolution, Humor

by John S. Wilkins | January 13, 2012

Sherlock Cumberbatch on Evolutionary Psychology

As always, click on the image to go see the entire Jonathon Rosenberg goodness

3 Comments

Filed under Evolution, Humor

by John S. Wilkins | January 12, 2012

You can’t explain a variable with a constant

Courtesy of reader Jocelyn Stoller, comes this video, of respected philosopher of science Jim Woodward discussing whether or not religious beliefs explains things like suicide bombing and the moral right in the US.

Answer: not likely. Watch part 2 at Youtube.

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Filed under Philosophy, Religion, Science

by John S. Wilkins | January 12, 2012