Thursday, 29 October 2015

An ensemble of evolutionary theories

Various folk have expressed concern that a generalized version of Darwinism that covers more phenomena would be weaker and would constrain expectations less - and would therefore be less useful.

John Maynard Smith once wrote:

The explanatory power of evolutionary theory rests largely on three assumptions: that mutation is non-adaptive, that acquired characters are not inherited, and that inheritance is Mendelian - that is, it is atomic, and we inherit the atoms, or genes, equally from our two parents, and from no one else. In the cultural analogy, none of these things is true. This must severely limit the ability of a theory of cultural inheritance to say what can happen and, more importantly, what cannot happen.

Recently, Alberto Acerbi has expressed a similar concern:

I am not convinced by the way-too-easy claims of “everything evolves!”, such as here, mainly because it seems to me that broad conceptions of evolution tend to have less explicative power

I've previously replied to Maynard Smith, writing:

Let's assume for a moment that his conclusion is true - and that it is harder to make predictions with cultural evolution than it is with biological evolution. So what? Theories of cultural evolution are not in competition with theories of biological evolution - they compete with other theories of cultural change that are less inspired by Darwinism.

Here I want to offer a different response - which is nonetheless still based on the idea that theories that cover different domains are not direct competitors.

Darwinism can be axiomatized. The axioms can be weakened and/or discarded, resulting in cut-down versions of Darwinism that apply under different circumstances. For example, conventionally, Darwinism requires copying. However without copying you can still have selection and goodness of fit - which are important components of Darwinism. Another common constraint involves what counts as a mutation. Random mutations constrain expectations a lot and result in easily falsifiable theories. However under some circumstances, such a constraint on mutation is not realistic. In cultural evolution, for example, it can be quite reasonable to model mental mutations as consisting of practically any change (short of recombination) that can happen inside an individual's mind. Mutations are still relatively small - but since they are the result of multiple generations of copying and selection within an individual's mind, they can be adaptive. Other Darwinian axioms can also be usefully weakened.

However, the resulting broad theories aren't in direct competition with the earlier narrow ones. They are applicable in different domains. As a result we have an ensemble of more-or-less Darwinian evolutionary theories - which are applicable under different circumstances. Having these extra theories in no way weakens the old, narrow versions of Darwinism from the textbooks. Those still work just as they did before. However the new, broader theories extend evolution into new realms, such as physics, chemistry, geology, astronomy and computer science.

Here's a diagram of the ensemble of evolutionary theories:

Theories vary along a one-dimension axis from 'specific' to 'general'. The more general theories are vaguer and constrain expectations less. However their corresponding advantage is that they are still applicable in application domains where narrower theories fail completely.

The expanded domain of evolutionary theory represented by universal Darwinism is like having a bunch of new tools in your toolbox. The complaints of John Maynard Smith and Alberto Acerbi are a bit like complaints that some of the new tools aren't as useful as one of the old tools was. That's OK - these are new tools that we didn't have before. You don't have to throw out any of your old tools in order to make room for the new ones. Instead, take delight in all the new things the bigger toolbox lets you do.

Of course this doesn't address the terminological debate about what deserves to be described as being 'evolutionary' or 'Darwinian'. However that's more of a 'small peanuts' debate, in my humble opinion. Universal Darwinism gives us a bunch of shiny new tools. We should try them out, see what they can do, and learn when best to use them.

Monday, 26 October 2015

My virtue signalling dilemma

I came up with the term 'virtue signalling' in 2011, and published about it here.

I made the term up after being irritated with Boyd and Richerson's term “heart on your sleeve hypothesis" from their "Solving the Puzzle of Human Cooperation" paper. It is often a bad idea to allow critics of a hypothesis to name it - and this was a case in point. Boyd and Richerson mentioned the signalling hypothesis mainly to criticize it while promoting their own rival ideas about group selection. By contrast, in my article, I promoted 'virtue signalling' to be the most significant cause of human cooperation after kin selection and reciprocity. A few other people have used the phrase before me - but never very seriously, it seems.

This article was written as part of my work on my 'Memes' book, which looked in more detail at culturally mediated cooperation than I had managed in my 2011 'Memetics' book.

Virtue signalling seems to be establishing itself as a popular term. However there's a foundational issue surrounding it which I haven't previously publicly addressed:

When I came up with the term I intended "virtue signalling" to refer to any kind of signalling self-worth - or denigrating of rivals. However, when I subsequently looked up the term 'virtue' in the dictionary I found that it had strong connotations of only referring to moral merit.

Clearly signalling of merit / worth / quality / value is a more general phenomena that just signalling moral goodness. I originally intended the term "virtue signalling" to refer to this more general idea. So, one of the examples I though of was a peacock signalling his 'virtue' to peahens. However, the dictionary suggests that the term 'virtue' means something more narrow: only moral merit.

One resolution would be to say that "virtue signalling" is a subset of "value signalling" - and that the latter includes Peacock signals, while the former does not.

The problem with this is that "value signalling" seems vague and ambiguous in other ways. It is already losing the popularity contest with "virtue signalling". I doubt whether this term has legs. Much the same goes for the other broader umbrella terms.

To deal with this, I'm inclined to double down on my original interpretation of the word 'virtue'. The dictionary does go on to offer some broader meanings of the term. Yes, describing a peacock's tail as a 'virtue' is a bit confusing, but I don't really see a significantly better solution. All signaling targets behaviour in the end - and what counts as 'moral' behaviour is pretty vague. So: we could also say that the peacock is signalling that having sex with it would be a 'good' thing to do.

Massimo's latest doubts

Massimo Pigliucci's latest doubts about cultural evolution can be found in the recent article: The Trouble with Cultural Evolution.

Alas, it's the same long-discredited nonsense as usual. Massimo doesn't know what he is talking about. I think at this stage one has to regard Massimo's writings as a case study in cognitive dissonance. How will Massimo continue to reconcile his doubts about Darwinian cultural evolution with the views of all the scientists who are now taking it seriously?

Massimo cites Lewontin's 1970 article "The Units of Selection. Explaining why he doesn't think the principles it lays down apply to cultural evolution. However, what he neglects to mention is that Lewontin stated himself that the principles did apply to cultural evolution in that very article. Here's what Lewontin said in 1970, on page 1:

It is important to note a certain generality in the principles. No particular mechanism of inheritance is specified, but only a correlation in fitness between parent and offspring. The population would evolve whether the correlation between parent and offspring arose from Mendelian, cytoplasmic, or cultural inheritance.

If you cite an article to support your position, and the author of the article disagrees with you in the same article, you should at least point that out.

Massimo's headache reminds me that one thing we haven't seen very much of so far is people publicly changing their mind on the topic. We clearly have a new generation of researchers who grew up with memes and understand the topic - but I've seen very few previous critics turn around and confess that they were mistaken. If scientists die before they change their minds on this topic, then we might be in for quite a lot more Darwinian revolution.

Update 2015-12-03: Massimo gloats over the reception of his paper here. It is all very well bending over backwards trying to find sympathetic interpretations of your opponents perspectives - but it is best not to bend over too far.

Sunday, 25 October 2015

US president references internet meme

I don't know if it's the first time, but it's the first time I currently know about.

Dawkins reads the section on memes from his latest book

Here, Richard Dawkins reads the section about memes from his latest book, Brief Candle in the Dark: My Life in Science.

The book has around three pages on memes. The content focuses on the efforts of Susan Blackmore and Daniel Dennett to turn memetics into a proper scientific enterprise.

Thursday, 22 October 2015

The function of ethics

From a biological perspective, ethical systems play several functional roles for their users.

In particular, ethics allows signalling virtue. Ethical systems are typically fairly other-oriented and they are frequently involved in manipulating the behavior of others. A shared ethical system can be a badge of group membership. A concern with ethics signals affluence: poor folk are more interested in means to obtain food and shelter.

These benefits are part of why humans are interested in ethics. However, from the perspective of memetics, these benefits aren't the real function of ethical systems - since they accrue to the human hosts involved. Since ethical systems are socially transmitted memeplexes it is reasonable to ask how their features benefit not their hosts, but themselves.

In memetics, the primary function of ethical systems is to spread. To do this, they need to be extensively publicly discussed. They also need to be taught to other individuals - the younger the better. This perspective probably helps to explain why there is so much public discussion about ethics. Not only do humans signal their virtuous nature to others by exhibiting their ethical systems, the ethical systems are themselves directly adapted to spread between hosts via teaching and instruction.

The signalling aspects of ethics play double-duty. On one hand, ethical signalling ethical content lets human hosts signal to other humans how virtuous they are - and how much spare time they have. The signalling of ethical content also directly helps ethical systems to spread.

Saturday, 17 October 2015

2014 attack on cultural evolution by Jerry Coyne

I got around to reading one of Jerry Coyne's more recent critiques of cultural evolution:

If evolution really weren’t based on heritable and permanent changes in DNA sequence, that would be surprising, and at least a major change in perspective. The “revolution” proponents argue that this does happen in two ways.

First, there is cultural evolution: stuff is passed on not by genes, but by learning. This, of course, is nothing new: Dawkins wrote about memes—units of cultural inheritance—way back in 1976, drawing a parallel between genetic and cultural evolution. But that was a parallel, and one that I don’t find terribly enlightening. But cultural inheritance is of course important in some species, including all animals that teach their young. The authors give some examples:

In addition, extra-genetic inheritance includes socially transmitted behaviour in animals, such as nut cracking in chimpanzees or the migratory patterns of reef fishes.

So what’s new? Yes, we can model how this works, but learning it itself an evolved ability, and modeling social evolution will involve things beyond the purview of evolutionary theory. Cultural evolution is not genetic evolution, and hence not part of the SET, which rests on changes in genes. Cultural evolution is important, but it’s no more part of SET than is the “evolution” of changes in automobile style over the years.

First let's look at the idea that "modeling social evolution will involve things beyond the purview of evolutionary theory".

Surely modeling DNA evolution involves things beyond the purview of evolutionary theory. It involves modeling aerodynamics, photosynthesis, echolocation, turbulence, biochemistry, structural stability, osmosis - and all manner of other things.

The idea that modeling cultural evolution goes beyond evolutionary theory while modeling DNA evolution does not seems like simply a basic confusion about the explanatory role that evolutionary theory plays.

As for: "Cultural evolution is not genetic evolution, and hence not part of the SET [Standard Evolutionary Theory], which rests on changes in genes" - that goes to the definitions of 'genes' and 'genetics'. If you have 'genetics' as the study of heredity, and 'gene' as the unit of heredity - as I favor - then cultural evolution is indeed genetic evolution, and does indeed involve changes in genes.

This is an argument about terminology. However, even without the terminological debate, defining the domain of evolutionary theory in terms of DNA genes - as Coyne curiously proposes - doesn't make any sense. Ultimately, this idea will be ditched as being based on an outdated classification scheme. Our ancestors weren't based on DNA, or descendants won't be based on DNA, and many modern evolving systems are not based on DNA. A DNA-based classification scheme is simply an impoverished one. It is deeply unscientific to divide evolutionary theory into evolution based on DNA genes and other kinds of evolution.

Monday, 12 October 2015

Natural sorting

You may have heard about natural selection. There's also natural sorting.

Sorting is a process which involves creating order out of disorder by rearrangement.

Sorting is ubiquitous in nature. There are pecking orders, lek rankings and dominance hierarchies. Rocks sort themselves by size on beaches and gasses sort themselves by density in the atmosphere.

In computer science, filtering and sorting get similar space on bookshelves. Knuth's epic volume 3 of The Art of Computer Programming is devoted to Sorting and Searching. This equal billing seems fairly reasonable to me.

However, sorting is rarely mentioned by physicists, biologists or evolutionary theorists. In evolutionary theory in particular, filtering seems to get all the limelight - while sorting is largely ignored.

I think the neglect of sorting is probably a case of terminology influencing thought. Selection is regarded as a central concept in evolutionary theory - while sorting doesn't enjoy the same status.

Whatever the reason for its neglect, sorting is a pretty important phenomenon. Environmental gradients are common (e.g. depth and altitude). Often organisms get sorted along the gradients - with the most competent organisms getting the best niches. For humans proximity to city centers results in an important gradient. The poorest humans get sorted to the outskirts by property prices - while a lot of courtship of the most desirable mates takes place in central locations.

Sorting and filtering are often combined in biological systems. Sorting is fairly often followed by filtering. In some cases the filtering is performed by mates - who choose the best partners they can find. In other cases, filtering is done by predators. For example, when a cheetah chases gazelles, the prey naturally sort themselves from fastest to slowest. The cheetah then filters out the slowest one.

It is worth noting that sorting has other effects on evolutionary dynamics that aren't much to do with sorting being a prelude to filtering. Consider assortative mating, for example. That's not really sorting followed by filtering - the sort itself is what affects the evolutionary dynamics.

It is possible to classify natural sorting into two main types based on the mechanism involved. Some types of sorting involve direct comparisons between neighbors. Others do not - and instead rely on different entities having different speeds or trajectories. Examples of sorts that do not involve direct comparisons between neighbors include the gazelle example above, electrophoresis and the ink diffusion spectrum phenomenon.

Sorting processes that involve neighbour copmparisons are dissipative: they create order and they need a power supply and generate heat. Sorting processes that don't compare the entities they are sorting tend to be more reversible. For example, a prism sorts light rays. However it isn't dissipative: the effect of a prism can be reversed by another prism. This observation suggests the names 'dissipative sort' and 'reversible sort' for the two categories of sorting processes.

Sorting is usually thought of as being a one dimensional phenomenon. However natural sorting also takes place in two and three dimensions. Here's a two-dimensional sort of ink pigments:

The dimensionality involved is not a defining characteristic of sorting processes.

It is sometimes possible to describe dissipative sorting operations in terms of selection. For example, when you shake your breakfast cereal, and the largest lumps rise to the top that process could be described as a series of many individual "selections" in which layers of the cereal act as porus sieves that allow small particles to fall through and select against large particles. This sort of re-description is possible for sorts that involve neighbor comparisons. It is usually less helpful to describe sorts that do not involve neighbor comparisons in terms of selection. Even where re-description in terms of selection is possible, describing sorting as a series of filtering operations is often long-winded and obtuse. It is usually best to simply describe sorting processes using the term "sorting".

One of the notable exceptions to the neglect of sorting by evolutionary theorists is John Wilkins. He has long been reframing natural selection in terms of sorting. I didn't get the idea from him, though I had long been aware of him framing evolution in terms of sorting. For an example of John's thinking on the topic see the "Evolution and Chance" FAQ.

Sunday, 11 October 2015

Memes and host lifespan

Cultural evolution has led to increased lifespans among many modern humans.

Symbiology has some basic models of how symbiotes affect host lifespan which seem likely to be applicable to cultural evolution. When a symbiont usually dies with its host, it can sometimes pay for it to divert resources from host reproduction into host maintenance processes. That makes the host live for longer and results in more opportunities for the symbiont to reproduce before it perishes with its host. Copies of individual memes do perish with their hosts - and this model is broadly consistent with the observed longer lifespans produced by cultural evolution to date.

However, there's an alternative scenario described by the same kind of model. If there's a lot of horizontal transmission of symbionts between hosts, the symbionts can sometimes profit by converting the hosts' resources into copies of their own heritable material as quickly as possible. This is the strategy employed by the Ebola virus, for example. Rather than increasing host lifespan, these types of parasite dramatically decrease it.

When does this latter scenario arise? The models are fairly specific about when this type of scenario is likely. It happens when the host density is high or when there's a lot of opportunities to spread between hosts.

The ability of memes to leap from host to host has dramatically increased over the last century. These days, mobile phones deliver memes pretty directly into peoples' brains in a near-constant stream. Horizontal meme transfer has increased dramatically in modern times - and it looks set to continue to rise. Our ability to pack humans together in huge cities has also continued to rise.

This raises some questions. What can be done to avoid going into an era in which memes shorten host lifespans - and rip through host resources like the Ebola virus does? Also, we have been seeing a lot of horizontal meme transmission for a while now. Yet if you look at the most meme-rich areas of the planet - such as Japan - host lifespans are excellent. Why are we not in an Ebola-like era already?

The most obvious answer is that memes that quickly kill their human hosts are selected against in various ways - by host immune systems, and by active suppression by groups of humans. People do get sucked into meme-spreading cults that rip through their resources Ebola-style - but education defends against this fate - and so do nearby friends and relatives.

An important reason for studying these dynamics is to see whether we can avoid problems. Will we see plagues of parasitic memes mirroring the 1918 flu epidemic? Will we see persistent draining influences - mirroring the effect of the HIV virus on lifespan in Africa? What about mixed bag pathogens? For example, smallpox helped Europeans to conquer native American tribes - while simultaneously killing many Europeans.

So far the influence of memes on lifespan seems consistent and positive. More memes are strongly correlated with longer lifespans. However I think it is too early to say whether this positive trend will continue without interruption. We should strive to understand these dynamics in order to help us to avoid problems in the future.

Tuesday, 6 October 2015

Susan Blackmore on machine ethics

Susan Blackmore weighed in recently on the topic of machine ethics - in article titled: It’s too late to give machines ethics – they’re already beyond our control.

While I generally think that students of cultural evolution ought to be well placed to contribute to prediction of the consequences of our actions in this area, I found several things to object to in Sue's analysis. On problem is the article's title. It strikes me as being defeatest. We ought to at least try.

Later in the article, Susan writes:

Replicators are selfish by nature. They get copied whenever and however they can, regardless of the consequences for us, for other species or for our planet. You cannot give human values to a massive system of evolving information based on machinery that is being expanded and improved every day. They do not care because they cannot care.

This seems like confused reasoning to me. We have examples of companies, governments and other organizations which have codified various human values. These are often in the form of 'laws' or 'rules'. If the argument is that memes and genes 'cannot care' because they are selfish replicators, then we have many examples of complex meme or gene products which do care - or behave as though they care.

Blackmore looks as though she is arguing from selfish memes to selfish organisms here. If so, that is a mistake parallel to the mistake that Richard Dawkins made in The Selfish Gene. Dawkins (1976) wrote:

I shall argue that a predominant quality to be expected in a successful gene is ruthless selfishness. This gene selfishness will usually give rise to selfishness in individual behavior. However, as we shall see, there are special circumstances in which a gene can achieve its own selfish goals best by fostering a limited form of altruism at the level of individual animals.

...and then...

Let us try to teach generosity and altruism, because we are born selfish.

He subsequently had to back-pedal, writing the following belated retraction (2006):

I do with hindsight notice lapses of my own on the very same subject. These are to be found especially in Chapter 1, epitomised by the sentence ‘Let us try to teach generosity and altruism because we are born selfish’. There is nothing wrong with teaching generosity and altruism, but ‘born selfish’ is misleading. In partial explanation, it was not until 1978 that I began to think clearly about the distinction between ‘vehicles’ (usually organisms) and the ‘replicators’ that ride inside them (in practice genes: the whole matter is explained in Chapter 13, which was added in the Second Edition). Please mentally delete that rogue sentence and others like it.
Selfish memes could result in selfish companies, governments and organizations - but it ain't necessarily so. Saying that such complex entities 'cannot care' seems like an unwarranted generalization to me. Maybe memes "cannot care" - but so what? It is memeplex products that we are mostly interested in when discussing machine intelligence. There's no good reason why they can't care.

Anyway, this topic is an important reason to study memetics. We need the best science has to offer to help us predict the consequences of our actions. The existing man-machine symbiosis probably won't last forever - there will probably be a merger or one side will assimilate the other. It looks as though we have enough power to be able to influence the outcome in a variety of ways - to the extent that technological determinism leaves some aspects of the outcome open. There's a lot at stake - and we should try our best to figure out what we should do.

Monday, 5 October 2015

Matt Ridley: Evolution of The Cloud

Matt Ridley: The Evolution of Everything

The book, "The Evolution of Everything: How New Ideas Emerge" by Matt Ridley is out later this month.

The book has its own domain: Here is the book on Google books and Amazon. Peter Forbes says it is Ridley's "magnum opus". High praise - since many of Ridley's other books are pretty good.

The book has a form of Universal Darwinism at its core. Ridley writes:

Indeed, to borrow a phrase from a theorist of innovation, Richard Webb, Darwinism is “the special theory of evolution”. But there is a general theory of evolution, too, and it applies to society, money, technology, language, law, culture, music, violence, history, education, politics, God, morality. The general theory says that things do not stay the same; they change gradually but inexorably; they show “path dependence”; they show descent with modification; they show selective persistence.

The special and general theories of evolution. I love it. What a great way to express the idea of Universal Darwinism. I don't like the term "Darwinism" being reserved for the "special" theory. Rather like Einstien, Darwin pioneered both the special and general theories of evolution; we should give him credit for that.

From the list of examples, it looks as though Ridley might be missing out on Darwinian Physics, though.

You may find that the first chapter is available free here. It's a philosophical/historical overview of bottom-up explanations.

Google Books has the first two chapters online here.