About the "Bell Curve"

Simply stated, [Murray and Herrnstein’s argument] goes like this: If the variation in a particular individual trait is caused by genes, then the difference in average values of the trait in populations must also be caused by the genes. In the I.Q. debate, this argument takes the following form: variation in I.Q. among individuals in a population is caused (to a large extent, at least) by each individual’s genes. For group A, the average I.Q. score is higher than for group B. Hence members of group A must, on average, have higher I.Q. genes than members of group B.

However plausible this sounds initially, the fallacy of this logic becomes immediately obvious with a little thought and the use of a popular analogy. If we randomly take some corn seed and plant it in uniform, rich, well-tended soil, we will get a distribution of plant heights whose variation is caused by their genes. If we take a sample of seed from the same source and plant in poor soil, we will again get a variation of heights that is caused by the genes. But the second group will have a lower average height than the first, even though the plants come from the same gene pool. This difference in average values is caused by the environment and not the genes, a fact known to every farmer.

So it is possible to have a variation that is purely genetic in some trait within a single group, while the difference in average values of the same trait between different groups is caused purely by environment. For example, the variation in individual heights has a substantial genetic component. But in Japan, which has been a relatively isolated country, average heights have risen considerably since World War II, a fact easily explainable by better nutrition.

https://freethoughtblogs.com/singham/2018/04/03/the-drearily-predictable-resurgence-of-the-race-and-iq-debate/

Intuition Pumps quotes by Daniel Dennett

Giving an intentional-stance* interpretation of some sub-personal brain structure is like putting a comment on a few lines of code; when done well, it provides an illuminating label, not a translation into English or other natural language of some formula in Brainish that the brain is using in its information-processing.

(*) the level of abstraction in which we view the behavior of a thing in terms of mental properties [wikipedia]

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In general, the cryptographer’s maxim holds: if you can find one solution to a puzzle, you’ve found the only solution to the puzzle. Only special circumstances permit as many as two solutions, but such cases show us that the existence of only one single solution to a question like this is not a metaphysical necessity, but just the immensely probable result of very powerful constraints.

People are much more complicated than either crossword puzzles or computers. They have convoluted brains full of neuromodulators, and these brains are attached to bodies that are deeply entwined with the world, and they have both an evolutionary and a personal history that has embedded them in the world with much more interpenetration than the embedding of a crossword puzzle in a linguistic community. So Ruth Millikan (for instance) is right that given the nature of design constraints, it is unlikely in the extreme that there could be different ways of skinning the cat that left two radically different, globally indeterminate, tied-for-first-place interpretations. Indeterminacy of radical translation* is truly negligible in practice. Still, the principle survives. The reason we don’t have indeterminacy of radical translation is not because, as a matter of metaphysical fact, there are “real meanings” in there, in the head (what Quine called the “museum myth” of meaning, his chief target). The reason we don’t have indeterminacy in the actual world is that with so many independent constraints to satisfy, the cryptographer’s maxim assures us that it is a vanishingly small worry. When indeterminacy threatens in the real world, it is always just more “behavioral” or “dispositional” facts—more of the same—that save the day for a determinate reading, not some mysterious “causal power” or “intrinsic semanticity.” Intentional interpretation almost always arrives in the limit at a single interpretation, but in the imaginable catastrophic case in which dual interpretations survived all tests, there would be no deeper facts to settle which was “right.” Facts do settle interpretations, but it is always “shallow” facts that do the job.

(*)  Radical translation is a term by W. V. O. Quine to describe the situation in which a linguist is attempting to translate a completely unknown language, which is unrelated to his own, and is therefore forced to rely solely on the observed behavior of its speakers in relation to their environment. [wikipedia]

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How can meaning make a difference? It doesn't seem to be the kind of physical property, like temperature or mass or chemical composition, that could cause anything to happen. What brains are for is extracting meaning from the flux of energy impinging on their sense organs, in order to improve the prospects of the bodies that house them and provide their energy. The job of a brain is to “produce future” in the form of anticipations about the things in the world that matter to guide the body in appropriate ways. Brains are energetically very expensive organs, and if they can’t do this important job well, they aren’t earning their keep. Brains, in other words, are supposed to be semantic engines. What brains are made of is kazillions of molecular pieces that interact according to the strict laws of chemistry and physics, responding to shapes and forces; brains, in other words, are in fact only syntactic engines. [..] Don’t make the mistake of imagining that brains, being alive, or made of proteins instead of silicon and metal, can detect meanings directly, thanks to the wonder tissue in them. Physics will always trump meaning. A genuine semantic engine, responding directly to meanings, is like a perpetual motion machine—physically impossible. So how can brains accomplish their appointed task? By being syntactic engines that track or mimic the competence of the impossible semantic engine.

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Natural selection is an automatic reason-finder; it “discovers” and “endorses” and “focuses” reasons over many generations. The scare quotes are to remind us that natural selection doesn't have a mind, doesn't itself have reasons, but it is nevertheless competent to perform this “task” of design refinement. This is itself an instance of competence without comprehension. Let’s just be sure we know how to cash out the scare quotes. Consider a population with lots of variation in it. Some members of the population do well (at multiplying); most do not. In each case we can ask why. Why did this one have surviving offspring while these others did not? In many cases, most cases, there is no reason at all; it’s just dumb luck, good or bad. But if there is a subset, perhaps a very small one, of cases in which there is an answer, a difference that happens to make a difference, then what those cases have in common provides the germ of a reason. This permits functionality to accumulate by a process that blindly tracks reasons, creating things that have purposes but don’t need to know them. The Need to Know principle reigns in the biosphere, and natural selection itself doesn't need to know what it’s doing. So there were reasons before there were reason-representers. The reasons tracked by evolution I have called “free-floating rationales," [...] There are reasons why trees spread their branches, but they are not in any strong sense the trees’ reasons. Sponges do things for reasons; bacteria do things for reasons; even viruses do things for reasons. But they don’t have the reasons; they don’t need to have the reasons. There are reasons aplenty for these behaviors, but in general, organisms need not understand them. They are endowed with behaviors that are well designed by evolution, and they are the beneficiaries of these designs without needing to know about it. This feature is everywhere to be seen in nature, but it tends to be masked by our tendency, adopting the intentional stance, to interpret behavior as more mindful and rational than it really is.

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Then what might the self be? I propose that it is the same kind of thing as a center of gravity, an abstraction that is, in spite of its abstractness, tightly coupled to the physical world. [...] It may be a “theorist's fiction,” but it is a very valuable fiction from which a lot of true predictions can be generated. [...] What then is a center of narrative gravity? It is also a theorist’s fiction, posited in order to unify and make sense of an otherwise bafflingly complex collection of actions, utterances, fidgets, complaints, promises, and so forth, that make up a person. It is the organizer of the personal level of explanation. Your hand didn't sign the contract; you did. [...] In the same way that we can simplify all the gravitational attractions between all the parts of the world and an obelisk standing on the ground by boiling it down to two points, the center of the earth and the center of gravity of the obelisk, we can simplify all the interactions—the handshakes, the spoken words, the ink scrawls, and much more—between two selves, the seller and the buyer, who have just completed a transaction. Each self is a person, with a biography, a “backstory,” and many ongoing projects. Unlike centers of gravity, selves don't just have trajectories through space and time; they gather as they go, accumulating memories and devising plans and expectations.

Teatro

The Universe is a messy and dangerous place. Fitness is not an optional policy in the natural selection perpetual genocide. The successful life-and-death stories of our ancient primate ancestors were imprinted in our genes. They still partially define, even today in our complex social world, what 'human' means. Our brains and bodies have default mechanisms that shape and limit our cognitive abilities, our ability to learn and remember, to reason and feel, to introspect. What we recognize as 'I'.

For fitness sake, the evolution of our actions, our behavior, converged to pursue (desire) certain sensations -- feelings, brain states -- and avoid (fear) others. Two examples are sexual arousal and pain, respectively. We are able to learn that different contexts favor different sensations. We adapt and manage our desires and fears to serve the multilayered goal of survival (multilayered in the sense of being made of several, more specific sub-goals but also for having multiple and not necessarily compatible solutions).

One powerful factor in this emotional and sensorial ecosystem is society. Society inhibits or enhances sensations, desires and goals through social conditioning not necessarily concerned with individual survival. One example is how nationalism is able to transfer and corrupt the genetic instincts of family into social norms to better serve the preservation of a national concept. However, this reshaping is not arbitrary, since it is impossible to remove our primitive genetic behavioral heritage without losing the person within. Humans minds are elastic but they are not blank slates. The resulting individual behavior turns out to be quite subtle in complex societies, forcing part of our genetic past into sleep mode, hardly detected in normal, non stressful situations. Herein, we are not that different from most social mammals.

But we humans are not satisfied with just that. Humans are active believers, constantly inserting meaning into the world stuff and into the mind stuff. We are addicted to belief and cannot help ourselves. One important side effect is value. A value is determined by the desire/fear intensity for a certain sensation. It is natural for us to classify a goal towards a attractive (repulsive) sensation has having a good (bad) value. And then that goal's value contaminates the cognitive architecture: a good (bad) goal must come from virtuous (vicious) desires and promotes right (wrong) actions. We elaborate enormous cognitive structures around the value concept. Ethics, Politics and Religion are basically arguments -- logical, empirical, traditional, dogmatic arguments -- to shape how values, virtues and righteousness are mapped. We feel that something has value, that acting such and such is right, but these are just instances of the mind projection fallacy. They are the result of our unrestrained use of meaning inception. They are internal mind attributes not external features of those somethings. We do not avoid something because it is bad, we define as bad those things we want to avoid.

This does not imply that meaning is arbitrary or relative. We are social animals after all, and share sensations, desires, goals. Our biology and cognitive apparatus is the same. So, at least for homo sapiens, this mapping does not have that much variability. Pain, say, is intrinsically a sensation to avoid. It is no surprise that violence towards other humans is usually considered a wrong action or that, for promoting violence, political and religious leaders choose first to dehumanize the enemy.

And where is consciousness in all this? Consciousness is not necessary for this sensation/desire/goal structure nor for the resulting behavior. Many different animals seem to be equipped with them and still don't seem to possess consciousness. Also, consciousness is not necessary for choice. A simple mechanism is able to make choices when faced with multiple options (even a thermostat has capacity for binary choice). A choice is the process of selecting an action among possible actions. It can be described in algorithmic terms (one classical definition is the maximization of expected utility) and, at least in its basic form, does not need cognition. However, perhaps consciousness provides value assignment to goals. Perhaps human consciousness includes (is?) our belief generator. Perhaps consciousness is a cognitive  and social contagious infection which the symptoms are persons. Who knows how to untangle a metaphorical web using just its metaphors?

We need beliefs to fictionalize an impersonal world, filing it with meaningful narratives, appropriate reasons and reasonable causes. We also need a world with persons. Other persons and ourselves. But an indifferent Universe does not offer anything like that, only pain and pleasure, life and death. So why not, collectively, make up everything else? 

Percepção e Cultura

Os japoneses usam a palavra 'azul' descrever a luz verde dos semáforos. Esta particularidade deriva de, antes do período moderno, existir apenas uma palavra para os tons de azul e verde (ao). Por volta do século XI surgiu na literatura uma outra palavra para designar um tom esverdeado de azul (midori). Este tipo de conceito é comum também em português (e.g., escarlate é um tom de vermelho, mas não é normalmente considerado uma cor independente). Já no século XX, em parte por influencias culturais externas, midori foi promovida a cor, apesar de ainda restarem cicatrizes antigas como a designação da cor dos referidos semáforos. Esta falta de distinção ocorre noutras linguagens. Na Bíblia Hebraica ou na Odisseia de Homero, não existe palavra para azul. [1]

O mapa das cores é um espaço contínuo de tonalidades, e as cores são um sistema discreto de classificação. Existe sempre uma perda nesta discretização que, por sua vez, é cultural e historicamente contingente mas também dependente da forma como funcionam os nossos olhos e o nosso cérebro. Mas qual a influência da cultura? Brent Berlin and Paul Kay, nos anos 1960, procuraram regras universais que regiam como as culturas lidam com o espaço cromático. Eles descobriram que existem entre 2 e 11 nomes para as cores principais. E que quando existiam X cores, estas tendiam a ser as mesmas.

Segundo o diagrama, se uma cultura usa apenas duas cores, estas serão o branco e o preto (claro/escuro). Se uma cultura usa três cores, a terceira tendencialmente é o vermelho. E assim sucessivamente. Quando se chega à sexta cor é o momento em que o azul se separa do verde. Das 98 línguas estudadas, 92 seguiam este padrão.

E em português? É curioso como temos nomes para vários tons relacionados com vermelho (escarlate, laranja, púrpura, violeta, roxo, magenta) mas quase nada para o verde. No entanto, se olharmos para a seguinte foto dificilmente podemos afirmar que predomina uma única cor (verde) quando realmente há vários tons de verde e que apenas nos falta vocabulário para os nomear.

A cor é uma noção subjectiva, não existe 'lá fora', tendo apenas presença na imagem que o cérebro constrói para mapear o que o rodeia. O mesmo se passa com sons, sabores, a sensação de calor e outra informação recolhida pelos nossos vários sentidos. O vocabulário para cor, porém, ajuda-nos a processar de forma distinta uma parte do 'nosso' mundo, o umwelt (a selecção natural tende a eliminar os sentidos menos úteis em ralação à região habitada pela respectiva população). Um conjunto rico de palavras para cor permite uma maior qualidade da percepção, uma recolha mais fina da informação disponível. A foto acima seria mais rica se a língua portuguesa tivesse dez palavras distintas para verde. E a cor é apenas uma dimensão possível. Um botânico ou um jardineiro retirariam ainda mais detalhe da mesma foto. Àparte das nossas limitações cognitivas, uma cultura e uma língua mais ricas conceptualmente tornam a nossa visão do mundo numa experiência também ela mais rica.  

[1] http://www.empiricalzeal.com/2012/06/05/the-crayola-fication-of-the-world-how-we-gave-colors-names-and-it-messed-with-our-brains-part-i/ 

Adaptação

"[The Dis] wanted their civilization to last forever— that's the one thing we do know about them. They built for the ages in everything they did. The evidence is that they did last a very long time— maybe eighty million years. But early on, they discovered a disquieting truth we are only just learning ourselves. It is this: Sentience and toolmaking abilities are powerful ways for a species to move into a new ecological niche. But in the long run, sentient, toolmaking beings are never the fittest species for a given niche. What I mean is, if you need tools to survive, you're not well fitted to your environment. And if you no longer need to use tools, you'll eventually lose the capacity to create them. It doesn't matter how smart you are, or how well you plan: Over the longest of the long term, millions of years, species that have evolved to be comfortable in a particular environment will always win out. And by definition, a species that's well fitted to a given environment is one that doesn't need tools to survive in it.

[...]

"It's the same with consciousness. We know now that it evolves to enable a species to deal with unforeseen situations. By definition, anything we've mastered becomes instinctive. Walking is not something we have to consciously think about, right? Well, what about physics, chemistry, social engineering? If we have to think about them, we haven't mastered them— they are still troublesome to us. A species that succeeds in really mastering something like physics has no more need to be conscious of it. Quantum mechanics becomes an instinct, the way ballistics already is for us. Originally, we must have had to put a lot of thought into throwing things like rocks or spears. We eventually evolved to be able to throw without thinking— and that is a sign of things to come. Some day, we'll become like the people of Dis, able to maintain a technological infrastructure without needing to think about it. Without needing to think, at all…

"The builders of Dis faced a dilemma: The best way to survive in the long run on any world they colonized was to adapt yourself to the environment. The best survivors would be those who no longer needed technology to get by. They tried to outlaw such alterations, but how do you do such a thing for the long term without suppressing the scientific knowledge that makes it possible? Over tens or thousands of millennia, you can only do this by suppressing all technological development, because technologies intertwine. This tactic results in the same spiral into nontechnological life. So inevitably, subspecies appeared that were better survivors in a given locale, because they didn't need technology in that locale. This happened every time, on all their worlds.

"The inhabitants of Dis had studied previous starfaring species. The records are hard to decipher, but I found evidence that all previous galactic civilizations had succumbed to the same internal contradictions. The Dis-builders tried to avoid their fate, but over the ages they were replaced on all their worlds by fitter offspring. These descendents had no need for tools, for culture, for historical records. They and their environment were one. The conscious, spacefaring species could always come back and take over easily from them. But given enough time… and time always passes… the same end result would occur. They would be replaced again. And so they saw that their very strength, the highest attainments they as a species had achieved, contained the seeds of their downfall.

"This discovery finally explained to us why toolmaking species are rare to begin with. It takes an unusual combination of factors to create a species that is fit enough to survive, but at the same time is so unfit in its native environment that it must turn to its weakest organ, its brain, for help. Reliance on tools is a tremendous handicap for any species; only a few manage to turn it into an asset.

"The builders of Dis knew they were doomed. We all are: technological civilization represents a species' desperate attempt to build a bubble to keep hostile environments at bay. Sentient species also never cooperate with one another over the long term, because the environments they need in order to live are incompatible. Some, like the Chicxulub, accept this easily and try to exterminate everyone else. Even they can't stop their own evolution and so eventually they cease to be starfaring species. Destruction or devolution are the only choices."

Karl Schroeder - Permanence

Selecção Natural

Uma citação de Richard Dawkins retirada do livro "The God Delusion" que resume o essencial da selecção natural, do ponto de vista genético:

In its most general form, natural selection must choose between alternative replicators. A replicator is a piece of coded information that makes exact copies of itself, along with occasional inexact copies or 'mutations'. The point about this is the Darwinian one. Those varieties of replicator that happen to be good at getting copied become more numerous at the expense of alternative replicators that are bad at getting copied. That, at its most rudimentary, is natural selection. The archetypal replicator is a gene, a stretch of DNA that is duplicated, nearly always with extreme accuracy, through an indefinite number of generations. [...] In the world of genes, the occasional flaws in replication (mutations) see to it that the gene pool contains alternative variants of any given gene - 'alleles' - which may therefore be seen as competing with each other. Competing for what? For the particular chromosomal slot or 'locus' that belongs to that set of alleles. And how do they compete? Not by direct molecule-to-molecule combat but by proxy. The proxies are their 'phenotypic traits' - things like length or fur colour: manifestations of genes fleshed out as anatomy, physiology, biochemistry or behaviour. A gene's fate is normally bound up with the bodies in which it successively sits. To the extent that it influences those bodies, it affects its own chances of surviving in the gene pool. As the generations go by, genes increase or decrease in frequency in the gene pool by virtue of their phenotypic proxies.

[...]

For didactic purposes, I treated genes as though they were isolated units, acting independently. But of course they are not independent of one another, and this fact shows itself in two ways .First, genes are linearly strung along chromosomes, and so tend to travel through generations in the company of particular other genes that occupy neighbouring chromosomal loci. [...] The other respect in which genes are not independent [...] concerns embryology which - the fact is often mis-understood - is completely distinct from genetics. Bodies are not jigsawed together as mosaics of phenotypic pieces, each one contributed by a different gene. There is no one-to-one mapping between genes and units of anatomy or behaviour. Genes 'collaborate' with hundreds of other genes in programming the developmental processes that culminate in a body, in the same kind of way as the words of a recipe collaborate in a cookery process that culminates in a dish. It is not the case that each word of the recipe corresponds to a different morsel of the dish. Genes, then, co-operate in cartels to build bodies, and that is one of the important principles of embryology. It is tempting to say that natural selection favours cartels of genes in a kind of group selection between alternative cartels. That is confusion. What really happens is that the other genes of the gene pool constitute a major part of the environment in which each gene is selected versus its alleles. Because each is selected to be successful in the presence of the others - which are also being selected in a similar way - cartels of co-operating genes emerge.

[...]

Different kinds of gene cartel emerge in different gene pools. Carnivore gene pools have genes that program prey-detecting sense organs, prey-catching claws, carnassial teeth, meat-digesting enzymes and many other genes, all fine-tuned to co-operate with each other. At the same time, in herbivore gene pools, different sets of mutually compatible genes are favoured for their co-operation with each other. We are familiar with the idea that a gene is favoured for the compatibility of its phenotype with the external environment of the species: desert, woodland or whatever it is. The point I am now making is that it is also favoured for its compatibility with the other genes of its particular gene pool. A carnivore gene would not survive in a herbivore gene pool, and vice versa. In the long gene's-eye-view, the gene pool of the species - the set of genes that are shuffled and reshuffled by sexual reproduction - constitutes the genetic environment in which each gene is selected for its capacity to co-operate.

Who’s Afraid of the Naturalistic Fallacy?

David Hume provided the classical statement of the view that moral values are the product of certain natural human desires. Hume argued that human behaviour is a product of passion and reason. Passions set the ends or goals of action; and reason works out the best available means of achieving these ends. Under this view, passions determine what humans find agreeable, desirable and valuable. Values are projected onto the world of objects and events by the passions in much the same way that colors are projected onto the world by the visual system. For this reason, Hume is said to have a subjectivist or projectivist theory of value. Whereas Hobbes argued that natural human passions were entirely selfish and that morality was an artificial invention, Hume argued that human nature included some passions – such as familial affection, sexual fidelity, sympathy and pride -- that promoted the common good. Hume called these moral passions, and argued that they constituted the basis of human morality.

[...] Although Hume’s theory is primarily a meta-ethical account of the nature and ontological status of morality, it segues into normative or substantive ethics in the following way. The ends supplied by the passions provide the first premises of chains of means-end reasoning. [...] It follows from this view of human psychology – and in particular, from this instrumentalist account of reason – that, in the absence of any passions, desires, or ends, reason alone cannot tell you what you ought to do. [...] one cannot go on justifying statements forever, one must come to a stop somewhere. And where one comes to a stop constitutes one’s meta-ethical theory. Theologians stop at divine commands, relativists stop at social conventions, Humeans stop at certain passions.

[...] The Humean-Darwinian argues that humans are equipped with a suite of adaptations for cooperation, that these adaptations constitute what have been called the moral passions or moral sentiments, and that these adaptations determine what people deem morally good and bad. If one accepts this argument, it makes no sense to complain that evolution may have explained why humans find certain things morally good, but it cannot tell us whether these things are really morally good or not. It follows from the premises of the argument that there is no criterion of ‘moral goodness’ independent of human psychology, and hence this question cannot arise.

Oliver Curry, Who’s Afraid of the Naturalistic Fallacy?, Evolutionary Psychology, 2006. 4: 234-247 [pdf]

Adaptação Moral

O instinto moral do Homo Sapiens evoluiu tal como a sua capacidade para falar. Não é coincidência que tabus como o incesto, o canibalismo ou o assassinato são praticamente universais. Eles são uma expressão de como os nossos processos cognitivos evoluíram há centenas de milhar de anos. Esta estrutura comportamental básica é independente das crenças regionais das populações humanas. Todo o regulamento moral expresso numa dada cultura derivou deste conjunto inicial, gravado algures no nosso cérebro. Fazê-lo melhor, com menos erros e arbitrariedades, mais apropriado às complexidades e exigências das sociedades actuais é um projecto similar à obtenção de qualquer outro tipo de conhecimento. Neste caso, é uma tarefa da ética, das ciências cognitivas e da psicologia comportamental.

A Few Question on Evolution

Este é um copy-paste do blog NeuroLogicaBlog escrito pelo Steve Novella, que contém diversos pontos interessantes sobre erros nas argumentações dos anti-evolucionistas.

Evolution and its pseudoscientific denial is a topic that comes up often on this blog. The comments to those posts, as well as e-mails resulting from my podcast, provide good fodder for discussion. I also think that confronting misconceptions is a very effective way to teach science, because it invariably involves exploring logic, evidence, and how we know what we know.

Here are a few recent tidbits I thought I would weave into a post.

Punctuated Equilibrium

SGU listener Michael Morrison e-mailed me about a discussion with his uncle, stating:

He stated that many scientists believe that there is not enough time in the history of the world for the current complexity of life to have developed through evolution. He stated that this problem was the impetus for developing the punctuated equilibrium theory and was just another example of scientists trying to explain away God. He referenced Frances Crick and his alien seed hypothesis as proof that even noted scientists recognize that lack of time is a problem for the theory of Evolution.

First, let me correct the misconception about punctuated equilibrium (PE) – it has absolutely nothing to do with there being enough time for evolution to have occurred. PE was developed by Gould and Eldridge to explain the apparent stability of species in the fossil record. Species do not constantly change, as Darwin surmised, but rather remain at rough equilibrium with their environment, punctuated by relatively rapid speciation or extinction events.

What PE means is that evolutionary changes tend to be compressed into short bursts, rather than occurring constantly and uniformly throughout nature. In the decades since the 1972 publication of PE, much evidence has emerged to support it, but also to show that there is no one mode or pace to evolution. Slow change also occurs within many species. [...]

Time Enough for Evolution

But let’s get to the core question here – has there been enough time for evolution to have occurred. Well, three plus billion years for all life on earth and 600 million years for multi-cellular life is an awfully long time. But is it enough?

Here is one of the better examples of this argument, from Laurence Smart, author of Unmasking Evolution. He makes a calculation concluding that there has not been enough time for an ape to have evolved into a human. Smart is an educator, but not an evolutionary biologist, and he displays multiple misunderstandings of evolutionary theory – but I will focus on this one argument.

His calculations are based upon a number of absurd assumptions. First, that all mutations are point mutations – one nucleotide changing at a time. Second, that it takes 300 generations for a new mutated form of a gene (allele) to completely replace the previous gene allele. And third, that only one mutation can be selected for at a time. None of these assumptions are well founded.

There are multiple mechanisms of genetic change, including those that involve entire genes or even entire chromosomes.The “one nucleotide at a time” assumption is patently false. Here is a list:

• Endosymbiosis
• Whole genome duplication (polyploidy)
• Chromosomal rearrangements
• Gene duplication
• Hybridization
• Gene displacement
• Horizontal gene transfer
• Jumping genes
• Sexual recombination
• Retrotransposons (Alu sequences)
• Exon shuffling and domain exchange
• Repetitious DNA and repetitious peptides

Further, there is no reason to assume one change at a time. Suites of mutations may be selected for, and there can be multiple overlapping selective processes happening at the same time. There is also no reason to assume that one mutation must reach 100% replacement before the next mutation can be selected for.

Further, Smart assumed a population of 100,000 individuals. The evidence suggests, however, that our ancestors passed through a time when the population was restricted to about 2,000 individuals. The smaller the population, the more quickly a new mutation can dominate the population. And in fact it is likely that most speciation events take place in small isolated populations.

So Smart’s calculations are worthless, and in the end there is no legitimate line of argument or evidence to suggest that there has not been enough time for evolution to have occurred.

I will add that if this were true – that current calculations show there has not been enough time for the evolutionary changes we observe to have occurred – this would not be evolution’s “dirty little secret” but rather a major focus of research. Scientists love when something does not fit, because it means we have a false assumption, which further means there is a major discovery waiting to be made. Evolutionary scientists are not tripping over themselves to solve this apparent anomaly, because it does not exist.

Evolution as a Designing Force

Commenter Sylvester left a rather incoherent comment on an older post, so I will reply here. He wrote (quotes are from my original post):

“Evolution is a designing force”= Who or What, and where is that force coming from?

“it has been shown that complex information can emerge spontaneously out of blind”= Out of blind??? wow! That sounds lke magic. Sorry but there is not hard evidence to support such claim.

This seems to be a real sticking point for most evolution-deniers – the notion that complexity can spontaneously emerge out of simple processes. Like Sylvester, they make what amounts to an argument from personal incredulity combined with a simple denial of evidence.

We talk of “forces” and “pressure” in evolution, but the terms are not meant to refer to physical forces – they are metaphors for evolutionary processes. An environmental condition can produce a “selective pressure” – meaning that there will be differential survival in a population (as opposed to random survival). Differential survival results in changing gene frequencies over time.

This is an internal process. Sylvester seems to think (I have to infer, as his comments are almost devoid of specifics) that by using the term “creative force” I was implying an outside force – I was not.

Information

He continues:

“If you start with one version of a gene and then it mutates in one offspring but not in another – now you have two versions of that gene. That represents an increase in information”= Not at all. Duplication of information is not an Increment of information. You are misusing the meaning of this word. To increase information is to obtain more complex information from previous information sources. Not duplication.

Sylvester misunderstood my point and misunderstands the concept of “information” – as do Intelligent Design proponents. First, I did not say that the mere duplication of the gene results in an increase in information. Rather, I very specifically said that the duplication followed by differential mutations results in increased information – because now we have two different versions of the gene, where there was one version before.

That is, by definition, more information. It would take more information to completely describe the two genes that it would their single parent gene. Sylvester simply missed what I wrote.

But further he then equates information to complexity – another common mistake of the ID crowd. Information has a mathematical meaning, and it has nothing to do with complexity. In fact, randomness can be very information dense.

The now common example is to take a Word document with 1000 random characters, 1000 letter As repeated, and an essay with 1000 characters. If you then compressed these three documents (compression is the process of representing the document with the least amount of information possible) you will find that the random characters has the most “information” from a mathematical point of view – it does not compress as much as the other two.

This may seem counterintuitive, but it comes from using a sloppy definition of “information”, or casually switching among several operational definitions of “information.”

But, no matter how you slice it, two different genes is more information than either gene alone.

Thermodynamics

He then finishes with this point:

“there is nothing in thermodynamics that states that the Earth cannot use energy to create a local decrease in entropy.”= Perhaps a local decrease in enthropy but increasing the overall enthropy elsewhere. It seems like is a hard concept for you to digest. You still do not get it.

Huh? I am not even sure what he is saying here. My original point is that the decreasing entropy (or increasing complexity, order or information – however you want to say it) in the biosphere over time does not violate the laws of thermodynamics, as many evolution deniers still amazingly contend. This is because the earth is receiving energy, and that the process of life uses that energy to do work, and the result of that work can be a decrease in entropy.

Put another way, the earth is not a closed system – it is an open system receiving energy. Thermodynamics only states that in a closed system (not receiving energy) entropy must increase.

Earth’s local decrease in entropy is more than offset by increases in entropy elsewhere in the universe – for example in our own sun, which is increasing its entropy as it spews out energy.

What creationists are essentially saying is that (for example) an electric train cannot run by itself without an energy source, therefore the train is not running. Despite evidence that the train is in fact running, I can also point out that the tracks are plugged into the wall where they are receiving a steady 220 volts and using that electricity to run the electric trains. Sylvester’s response to this is typically incoherent. (And of course the irony of his final sentence is classic.)

Conclusion

Readers might think I am being unfair picking on Sylvester and Michael’s uncle – but their questions really are typical of the average creationist. In fact (although not as verbose or eloquent) this is typical of the best arguments from the leading lights of creationism and ID.

Creationist arguments are logically flawed, factually challenged, and often border on incoherent. What is worse, you can make a very plain and straightforward argument and they will often find someway to misinterpret it.

In fact I predict that very statement will be misinterpreted as an ad hominem against creationists, even though I specifically wrote “creationist arguments.”

But they are amusing, and can be a very useful tool for improving the public understanding of science.

Vantagens competitivas

O efeito placebo está estudado e bem documentado e, hoje, há suficiente evidência científica para crermos na sua existência. Isto significa que, numa época pré-médica, houve vantagem selectiva entre um crente nas enfabulações de um qualquer xamã em comparação com alguém menos sugestionável. Desta forma, ao longo de milhares de gerações, a pressão terá sido para aumentar a percentagem de crédulos nas populações humanas. Somos todos originários de linhagens com maiorias de crentes. As religiões do presente são apenas instâncias barrocas - porque antigas e prenhas de compromissos históricos e políticos ocorridos durante séculos de expansões e aglutinações - dessa vantagem em acreditar.

Um melhor mapa da Evolução...

... que é um acontecimento muito não-linear:

[via Phyrangula]

Um Retrato Norte-americano

Escolha

O poder (político, militar, religioso) tem semelhanças com o sistema imunitário. Ambos são desenhados para a manutenção de uma sociedade complexa que os suporta, ambos precisam de oponentes para continuarem fortes, tendo uma elite capaz de os eliminar, ambos, em caso de inacção, viram-se contra si próprios. Só que no poder a capacidade de auto-preservação é, em parte, da sua própria responsabilidade. Pode escolher o inimigo bem como difundir aos que subjuga, a mensagem necessária à sua sobrevivência.

O inferno não são os outros

A noção de Vida é um assunto que os biólogos têm cuidado a tratar. Conhecemos apenas um exemplo de vida (esta nossa, baseada no carbono e no ADN) e, por isso, os especialistas evitam apontar condições necessárias para que algo esteja vivo e preferem falar de condições suficientes à vida. Desta forma, não caem no erro de criar uma definição demasiado restrita e preocupam-se apenas em incluir o que entendemos serem seres vivos aqui na Terra. Grosso modo, as condições suficientes dizem que um ser é considerado vivo se possuir metabolismo (i.e., capacidade de processar energia vinda do exterior usando-a na sua manutenção e dissipando os restos) e seja capaz de se reproduzir (criando uma cópia sua, cuja qualidade dessa cópia é proporcional à possibilidade de sobrevivência pelo mecanismo da selecção natural). Curiosamente, olhando para estas condições de forma estrita, um animal ou vegetal sexuado que seja o último da sua espécie ou que se encontre irremediavelmente isolado, apesar de conter uma comunidade de seres que satisfazem os critérios (células, bactérias, fungos, parasitas...), não poderia considerar-se vivo.

Não existem suficientes mentes para albergar o explosivo crescimento da população de memes.

"As ideias podem ser perigosas. Darwin, teve uma, por exemplo. Nós responsabilizamos todos os tipos de inventores e inovadores por avaliarem, à priori, o impacto ambiental das suas criações, e como as ideias podem ter um impacto enorme do ambiente, não vejo razão para isentar os pensadores da responsabilidade de colocar em quarentena alguma ideia mortal que possam imaginar. Assim, se eu encontrar uma destas ideias, devo cerrar os meus lábios, estudá-la e reflectir até que encontre uma forma de a expressar de forma segura. [...] Mas aqui está uma ideia inquietante que há-de inevitavelmente de ser verdade, numa ou outra versão, e até onde posso ver, não é prejudicial publicitá-la. Talvez até ajude:

A população humana ainda está a crescer, mas não ao ritmo do crescimento dos memes. Existe uma competição entre memes para ocupar o espaço limitado dos cérebros humanos, e muitos terão de ficar de fora. Graças aos nossos brilhantes e incessantes esforços e ao nosso apetite insaciável por novidades, criámos um fluxo crescente de informação, em todos os meios de comunicação e em todos os tópicos e assuntos. Agora, ou (1) afogar-nos-emos em informação ou (2) não nos afogamos. Qualquer das alternativas é perturbadora. O que quero eu dizer por afogar? Que iremos ficar psicologicamente submergidos, incapazes de processar a informação disponível e realizar decisões sobre a nossa vida face à imensa quantidade de possibilidades e opções oferecidas. [...] Se não nos afogarmos, como vamos lidar com esta situação? Se, de alguma forma, aprendermos a nadar da crescente maré da infosfera, isso significará que nós -- ou seja, os nossos netos e bisnetos -- seremos muito diferentes dos nossos antepassados. Como seremos? O que quer que «nós» sejamos, ainda mamíferos, já robots, o que saberemos e o que teremos, para sempre, esquecido? O que acontecerá com as nossas referências culturais? Provavelmente os nossos descendentes reconhecerão algumas (as pirâmides do Egipto, a Aritmética, a Bíblia, Paris, Shakespeare, Einstein, Bach...) mas à medida que ondas e ondas de novidade passam sobre elas, o que perderemos? Os Beatles são maravilhosos, mas se a sua imortalidade cultural for comprada à custa de outras figuras do Século XX, como Billie Holiday, Igor Stravinsky, ou Georges Brassens (hmm... quem é este?) o que restará desta nossa cultura?

As diferenças intergeracionais que todos nós experimentamos, presumivelmente serão multiplicadas até ao ponto que a informação pura que todos armazenamos nos nossos gadgets serão incompreensíveis para os outros, excepto que teremos muitas pedras de Roseta inteligentes capazes de «traduzir» material estranho em formatos que (pensamos nós) seremos capazes de interpretar. [...] O que acontecerá ao nosso conhecimento comum no futuro? Penso que os nossos antepassados tiveram a tarefa facilitada: fora as informações discretas dos rumores e de alguns segredos de estado ou de comércio, as pessoas sabiam essencialmente as mesmas coisas, e sabiam que sabiam o mesmo. Simplesmente não havia muito que saber.

Eu vejo pequenos projectos que poderão nos proteger, até certo grau, se realizados com sabedoria. Pensem em todo o trabalho publicado em jornais científicos antes de, por exemplo 1990, que está em perigo de se tornar practicamente invisível para os investigadores porque não podem ser acedidos online por um bom motor de busca. Digitalizar tudo e disponibilizar na net não é suficiente pois há demasiada informação. Mas podemos criar projectos de comunidades virtuais formadas por investigadores reformados, com motivação e conhecimento dessas bibliotecas, que possam usar a sua experiência para seleccionar os melhores trabalhos tornando-os acessíveis à próxima geração de investigadores. Este tipo de actividade tem sido vista como um trabalho académico próprio para classissistas e historiadores mas não digno de cientistas de ponta. Acho que devemos mudar esta perspectiva e ajudar as pessoas a reconhecer a importância de providenciar, aos outros, caminhos mais claros entre as nossas florestas de informação. É uma gota de água, mas talvez se começarmos a pensar na conservação de informação valiosa, possamos salvar os nossos descendentes de um colapso informacional." adaptado do texto de Daniel Dennet em http://www.edge.org/q2006/q06_8.html#dennett

O objectivo da vida é dispersar energia

Texto de Scott Sampson [adaptado de http://www.edge.org/q2006/q06_3.html#sampson]

Muitos de nós estamos familiarizados com a 2ª lei de Termodinâmica, a tendência da energia para se dispersar, passando de um estado de maior para um de menor qualidade. Em termos mais gerais, como disse o ecologista Eric Schneider, «a natureza abomina o gradiente», onde gradiente significa apenas uma diferença (de temperatura, de pressão, por exemplo) ao longo de uma distância. Sistemas físicos abertos - onde se incluem a atmosfera, a hidroesfera ou a geoesfera - seguem todos esta lei, sendo levados a dispersar energia, em particular o fluxo de calor, tentando sempre atingir o equilíbrio. Fenómenos como o movimento de placas, os fluxos submarinos ou os furacões são manifestações da 2ª lei.

Há cada vez mais evidência que a vida, a bioesfera, não é diferente. É comum ouvir que a complexidade da vida contraria a 2ª lei (invocando uma divindade ou algum processo natural desconhecido). No entanto, a evolução e a dinâmica dos ecossistemas obedecem à 2ª lei funcionando em grande parte para dissipar energia. Eles não o fazem ardendo rápido e desaparecendo, como um fogo numa floresta, mas através de um fogo lento, de ciclos metabólicos estáveis que guardam energia e continuamente reduzem o gradiente solar (principalmente pela fotossíntese, pelas acção das bactérias e das algas).

Virtualmente todos os organismos, humanos incluídos, são transmutações da luz solar, passagens temporárias desse fluxo energético. A dinâmica ecológica, do ponto de vista termodinâmico, é um processo que maximiza a captura e degradação de energia. De igual forma, a tendência para a vida se tornar mais complexa nos últimos 3500 milhões de anos (bem como o aumento da biomassa e da diversidade dos organismos) não é simplesmente derivada da selecção natural, como muitos evolucionistas argumentam, mas também do «esforço» da natureza de absorver cada vez mais luz solar.

A ecologia tem sido resumida à frase «a energia flui, a matéria recicla-se». Porém, esta máxima aplica-se também aos sistemas complexos no mundo não-vivo; unindo literalmente a biosfera à geoesfera. Cada vez mais se percebe que os sistemas complexos, cíclicos, de matéria tem uma tendência natural para emergir face a gradientes de energia. Este fenómeno recorrente pode ter sido uma das forças motrizes para o inicial surgir da vida.

[...] O conceito da vida como um fluxo energético, uma vez totalmente digerido, é profundo. Como Darwin uniu o Homo Sapiens aos restantes animais, a perspectiva termodinâmica conecta inexoravelmente a vida ao mundo não-vivo. Se assim for, a evolução não é dirigida pelas maquinações de genes egoístas com o intuíto de se propagarem pelos milénios. O que pode ocorrer é a ecologia e a evolução operarem em conjunto como uma forma eficiente e muito persistente de reduzir o gradiente gerado pela estrela mais próxima. A minha opinião é que a teoria da evolução (o processo, não o facto da evolução!) e a biologia no geral, estão a dirigir-se para uma revolução uma vez entendida a noção que os sistemas complexos da terra e da vida não estão só inter-conectados mas também são inter-dependentes nesse constante reciclar de matéria para manter o fluxo de energia.

Cultura e Genética (última parte)

A inteligência social é uma característica comum aos primatas. O antropologista Robin Dunbar argumenta que esta é a principal razão pelo aumento da massa cerebral: existe uma forte correlação entre o tamanho do cérebro e a dimensão dos grupos sociais entre cada espécie. A inteligência tecnológica existe também noutros primatas (os chimpanzés usam ferramentas no seu ambiente natural) mesmo que a capacidade de construir ferramentas seja muito rudimentar (mesmo em cativeiro). Os Austrolopitecus usavam ferramentas mas não existem evidências de uma capacidade deliberada de construção. Já o Homo Erectus mostra uma grande evolução, com a manufactura de machados simétricos (indicando que o construtor tinha já uma imagem mental do objecto pretendido). Mas em tudo isto existe um enorme conservadorismo: um crescimento limitado tecnológico aliado a uma falta de capacidade de inovar. Mesmo nos humanos modernos existe evidência que mostra um grau de separação entre a inteligência social e a técnica. Por exemplo, os autistas são deficientes em entender o comportamento de outros humanos mas melhores que a média na compreensão de ferramentas e objectos inanimados.

Finalmente, existe uma óbvia selecção que favorece um melhor conhecimento do ambiente. Mas foi isto obtido através do aumento geral da inteligência ou a partir do desenvolvimento de um módulo mental específico? Em favor desta segunda opção, pode-se argumentar que todas as sociedades humanas partilham certas ideias do mundo natural. Primeiro, todos os seres vivos pertencem a um, e a um só, «tipo natural». Um animal é um cão ou um gato e por aí fora, necessita pertencer a uma espécie (não a zero nem a duas) e não muda de espécie. Segundo, partilhamos a ideia que os tipos naturais podem ser classificados hierarquicamente. Por exemplo, um cão e um leão são 'comedores de carne' (e não 'comedores de folhas'), mamíferos (não são repteis ou peixes) e animais (não são plantas). Estas atitudes humanas generalizadas podem reflectir uma predisposição inata. Em alternativa, elas podem ser universalmente aceites por serem praticamente verdade e seriam aprendidas pelas várias sociedades humanas devido representarem conhecimento importante. Um segundo argumento em favor de um módulo mental específico é a facilidade com que as crianças adquirem estas crenças.

Voltando ao argumento, o aumento do cérebro humano nos últimos cem mil anos foi associado com um aumento das três inteligências: social, técnica e de história natural. Porém, elas eram relativamente independentes. Milthen sugere com o advento da linguagem, incluindo a gramática, evoluiu também neste período. Apesar de ser difícil sugerir uma data mais precisa, a explosão cultural dos últimos 50.000 anos, que levou a um acumular progressivo de conhecimento, pode ter coincidido com o terminar da separação destes três módulos, acção na qual a linguagem terá tido um papel fundamental. Com a linguagem é possível estabelecer e comunicar aos outros analogias entre os três processos mentais (usamos a mesma gramática para falar de conceitos relativos dessas três áreas). Se este argumento estiver certo, devemos à linguagem o ter-nos libertado do conservadorismo que durou um milhão de anos durante o Paleolítico Inferior e colocar-nos no caminho da evolução cultural que se seguiu.

[adaptado do livro The Origins of Life de John Maynard Smith e Eörs Szathmáry]

Cultura e Genética (parte V)

Porque demorou tanto aos nossos ascendentes iniciar o processo cultural? O registo fóssil mostra a existência de ferramentas limitadas com um milhão e quatrocentos mil anos. O aumento cerebral acelerou nos últimos 300.000 anos, os modernos Homo Sapiens surgiram há 100.000 anos mas só desde há 50.000 anos se verifica uma evolução cultural contínua. O que explica estas diferenças temporais? E quando se originou a linguagem?

O arqueologista britânico Steven Mithen no seu livro A pré-história da mente de 1966 tenta uma resposta. A essência do seu argumento é a seguinte: A mente humana é realmente modular como sugerido por estudos de competência linguística. Durante a maior parte da evolução humana, estes módulos aumentaram de eficiência mas mantiveram-se, em larga medida, separados uns dos outros. A linguagem surgiu inicialmente como função social de comunicação mas providenciou um meio no qual essas barreiras podiam ser derrubadas. A explosão de criatividade dos últimos 50.000 anos resultaram do eliminar dessas barreiras. Mithen supõe a existência de três módulos mentais cujo objectivo seriam lidar com a inteligência social, a inteligência técnica e a história natural (i.e., o conhecimento do ambiente, dos seus perigos e virtudes). [cont.]

Cultura e Genética (parte IV)

Existem, claro, diferenças entre genes e memes. Os genes são transmitidos de pais para filhos. Os memes podem ser transmitidos horizontalmente, ou mesmo dos filhos para pais. Mas existe uma diferença ainda mais profunda sobre estes dois conceitos. Genes especificam estruturas ou comportamentos - i.e., fenótipos - durante o desenvolvimento. Na herança, o fenótipo morre e apenas o genótipo é transmitido. A transmissão dos memes é muito diferente. Um meme é um fenótipo, o análogo ao genótipo seria a estrutura neural no cérebro que especifica esse meme. Quando A conta a anedota a B o que é transmitido é o fenótipo (A não passa uma parte do seu cérebro a B). Daqui segue que a herança nos memes pode conter caracteres adquiridos: B ao receber a anedota pode criar uma variante ainda com mais piada, e transmiti-la a C já com as devidas alterações. Nesse sentido, a transmissão cultural é Lamarckiana. Por estas razões, não é possível usar a teoria da genética populacional aos memes.

Uma outra implicação da linguística é a noção da mente modular (cf. post anterior). Estudos sobre a linguagem e sua aquisição sugerem que a habilidade para falar não é um aspecto relacionado com a inteligência geral, mas sim uma competência específica. Como Noam Chomsky argumenta, nós temos um «orgão da linguagem». A evidência desta perspectiva levou à sugestão que o cérebro possui competências específicas para certos domínios. No jargão actual, diz-se que o cérebro é modular (conceito que tem sido reforçado em estudos neurológicos tanto em pessoas normais como em pacientes que perderam parcelas de massa cinzenta). [cont.]

Cultura e Genética (parte III)

É claro que os seres humanos dependem da aprendizagem observacional, reforçada pelo ensino, que inclui instruções verbais. Se existem animais capazes de copiar os seus pais e avós porque não surgem avanços culturais continuados nas suas sociedades? Duas sociedades de chimpanzés podem ter hábitos distintos mas ambas não estão continuamente a adquirir novos hábitos. Uma resposta provável é que, nos humanos, a principal ferramenta por onde a cultura é transmitida é a linguagem.

Tanto o sistema genético como o sistema linguístico são capazes de transmitir um conjunto indefinido de mensagens construídas como sequências lineares baseadas num pequeno número de unidades diferentes. Na genética, a sequência das quatro bases (ACGT) especifica um grande número de proteínas que, por sua vez, especifica um número indefinido de morfologias. Na linguagem, a sequência de 30 ou 40 fonemas especifica muitíssimas palavras cujo arranjo (segundo uma dada gramática) permite elaborar um indefinido número de significados.

Richard Dawkins acentuou esta analogia ao introduzir o conceito de meme, uma unidade de herança cultural semelhante ao gene. Um meme, argumenta ele, é um replicador. Uma dada anedota, por exemplo, ao passar de A para B, forma uma representação no cérebro de B que pode ser visto como uma replicação da anedota original. Existe espaço para selecção: uma boa anedota replica-se mais facilmente que uma má. Claro que o sucesso da replicação depende da natureza da mente humana bem como do meio cultural onde ela existe. Mas o mesmo pode ser dito sobre os genes: o seu incremento depende do ambiente e do conjunto de outros genes que estão presentes. [cont.]