Darwin's Dangerous Idea
Daniel C. Dennett
Penguin Books. First published 1995.
The 'dangerous idea' is set out by Dennett as follows. '...evolution by natural selection occurs whenever the following conditions exist: (1) variation: there is a continuing abundance of different elements. (2) heredity or replication: the elements have the capacity to create copies or replicas of themselves. (3) differential "fitness": the number of copies of an element that are created in a given time varies, depending on the interactions between the features of that element and features of the environment in which it persists.'
As far as it goes, this is alright, and fits in exactly with what I know of the rather subtle theory of evolution propounded by Darwin. The theory needs reiteration, because the simplified, Twitter-style 'handle' that is often used to describe it - 'survival of the fittest' - does not sufficiently protect the theory from misrepresentations and accusations of circular argument. Though the statements in paragraph above are deliberately not formulated as specific to biological systems, Darwin, of course, devised his theory to explain the origin of the myriad species of life forms on earth. Restated in the light of subsequent discoveries in genetics and molecular biology, the theory could start with DNA undergoing random mutations, one of which could increase the 'fitness' of the parent organism to exist and procreate in its environment. This results in a greater number of replicates of the fitter mutant in the succeeding generations. When this algorithm, as Dennet calls it, is iterated over millions of generations, it leads eventually to today's billions of different species, bacteria and bugs and worms and frogs and birds and cockroaches and snakes and whales and sharks and apes and humans and elephants and ...., all starting from very elementary life forms, i.e. single celled organisms. Or something even simpler, but here we go into the somewhat murky realms of prebiotic evolution. More on this later, trying to examine whether the idea can actually be applied 'downwards', towards molecules and atoms and subatomic particles - and 'upwards', to social organisation, to human self awareness and consciousness, and to the arts, artifacts and creativity. Dennet appears to think it can, and hence gives it the appellation 'dangerous'.
But the theory as stated above is open to an unwarranted inference, which must here be specifically denied. Evolution does not lead necessarily to life forms that are, in any absolute sense, 'better' with each succeeding generation. The mutant organism is able to multiply better - and it need to do that only marginally better - than the non mutants; this is sufficient to ensure its survival with a slightly greater probability. Many, many such mutations leads to speciation, but the new species so generated cannot be compared to each other on any absolute moral or intellectual grounds to chose one as a higher life form, and the other as a lower. Consider that all - ALL - life forms extant today have evolved from the same primordial single celled creature. Clearly the meanest bacteria we may identify today have evolved - become 'better and better' - over the same period of approximately 4 billions of years, taking as long to reach their current forms as the greatest humans. Thus in evolutionary terms, the Tree of Life does not necessarily reach to greater and greater intellectual or moral heights, becoming narrower as it grows, with humans at the very tip. It spreads as it grows, and though many branches die out (dinosaurs, for example) others are formed, until now, at the very top, we have all these billions of species, all equally evolved, all having gone with equal success through the various fitness filters. (The upward direction in the Tree of Life corresponds, of course to the Arrow of Time, with the very top representing the present day).
In fact, a tree is not the correct metaphor. In the light of what we know about 'jumping genes' and horizontal transfer of genetic information, even from bacteria to the 'higher' organisms, it would be more correct to represent the relationships between the species as a network, the branches of the tree not growing isolated from one another, but establishing contacts with other branches even after a considerable amount of evolutionary time. However, the horizontal connections are, at this point of time, not known to be as strong or extensive as the vertical ones.
A possible misunderstanding about the nature of evolution also arises from the apparent requirement of greater 'fitness' for each succeeding generation. We may ask - fitness for (or to) what? 'Fitness to (or for) the environment' is the obvious answer. But note firstly that environment does not remain the same with time or with geography. While allopatric speciation (i.e. different species arising in different geographies) may be an indication of the variation of the requisite fitness with geography, how do we explain sympatric speciation (different species arising in the same geography)? Even the smallest micro-environments (a small pond or a puddle, for example, or a small grove of trees) are populated by numbers of different species, all of them having evolved over the same amount of time, and all of them equally fit for the particular environment. The theory of evolution, of course, accommodates this easily by describing how different species occupy different niches within the same environment, or micro-environment, and how mutations which rendered the organism less fit in one geography may be adapted to make it more fit when it moves to a different environment. But note that there are many equally successful, and therefore equally good, ways for an organism to speciate in response to the challenges of a particular environment. There is no absolute scale on which to measure one way as somehow better than another, morally or ethically. On these terms, cockroaches are as 'good' as humans, perhaps better, for, as a species, they have survived longer.
A second point to note in the context of sympatric evolution is the idea of 'neutral drift' proposed by Kimura. Here the mutations, which of course occur randomly, have no effect on the fitness of the individual, neither good or bad. Speciation occurs simply by a random drift of the genes from a set corresponding to one species to that corresponding to another, both with equal fitness values, and passing through stages which also do not affect the fitness. Of course, mutations which improve the fitness would be selected for, while those that decrease it (by far the largest number of individual mutations) would be selected against. But many that survive and carry on to subsequent generations would have no effect. This idea, too, like the ones above, does not give any special moral or ethical stature to any one species.
The common feature of all the above arguments (and there are many more, all within the broad umbrella of the theory of evolution originally stated and established by Darwin, and many fiercely contested among scientists) is that we need not postulate any intelligent designer, commonly called God, superior to all life forms, who made the species. Variation, replication and natural selection are sufficient to generate the present day biosphere. (To digress a bit, there are those who claim that, while God may not have actually made the species, he may have made the rules, or the algorithms, that make the species. There is, of course, a clear and logical refutation of this, but that's an argument for another day.)
Dennett pushes this idea right from the beginning, and makes it clear that when he is critical of one or another theory of evolutionary science, he is not speaking up for religion, or for creationism, or for God. He casts his lot firmly among the atheists, and the one writer on evolution he consistently speaks of approvingly is Richard Dawkins. He is less charitable to many others, and is specially critical of Stephen Jay Gould and Noam Chomsky, seeming at times to have written the book just to dis the two.
Stephen Gould is one my favourite writers on biological topics. His writings are immensely popular and influential among thinking laymen. Some of his essays may be superficially read as being dismissive of Darwinism, and though he himself has always spoken out against creationism, American proponents of 'equal time' in the school syllabus for the Biblical version of creation have used his writings to imply that all is not well with Darwinism. Dennett allows that Gould is not a supporter of an a-Darwinian explanation of creation, but attacks at least two of the main modifications the latter has suggested to the basic theory. One is Gould's contribution to the debate on gradualism versus catastrophism. Simply put, on one side are those who believe that small changes, very small changes, sieved through the process of replication and natural selection, gradually and incrementally lead, over the eons, to speciation. On the other side are those that claim that evolution occurs in sudden and (geologically) rapid spurts that intersperse long, generally quiescent eons, during which little speciation occurs. Gould is on this side and calls his own version of this 'punctuated equilibrium'. He expounds this idea very well in his book 'Wonderful Life'. Dennett, for reasons which are not very clear to me from his book, appears to consider this against the laws of physics. Such an idea, he claims, is akin to postulating what he calls a 'skyhook', an mysterious and unknown device that somehow pushes evolution forward. This is wrong, he says, unscientific, and importantly, unnecessary. The advances in evolution are instead helped on by 'cranes', small changes that make an organism a little better. I suppose an example of cranes, and cranes upon cranes, and so on, leading to complex structures is the description of a possible pathway to the development of an animal eye in 'The Blind Watchmaker' by Richard Dawkins. Dawkins talks about a mutation leading to a primeval eye consisting of just a few cells a little more sensitive to light than the others, which would help the organism with that mutation move in the direction where there is more food (or less predation), and this slowly developing, over hundreds and thousands of generations, into a proper eye.
But there is no specific evidence against rapid changes, and we know from the study of non-linear systems in physics that sudden and large changes in a system could arise from a small change in the input (as in weather systems, for example). Thus there is nothing wrong, scientifically, in postulating such 'skyhooks'. The sudden disappearance of dinosaurs, over a geologically insignificant period of a few millions of years some 65 million years ago is an example of a rapid turn in the course of evolution, though this is thought to have been triggered by the impact of a large meteroite, not just a 'small input'. Another example of a so-called 'skyhook' postulate that invites Dennett's disparagement is Noam Chomsky's idea that the human anatomy and brain is hard-wired for the faculty of language, as in no other primate, and that this faculty probably arose by some sudden and specific developments (Chomsky doesn't actually say genetic mutations, but doesn't deny them either) maybe a few hundred thousand years ago, when the human line diverged from the other apes. Dennett laughs this off, and claims that slow changes by the basic Darwinian algorithm should be sufficient to lead to language, and further to human culture.
Dennett also takes up cudgels against another proposal made by Gould. Not all features seen in living systems are adaptations that increase the fitness of the organism, said Gould. In many medieval buildings, when a circular dome is placed on a base which is square-shaped, there are roughly triangular portions between the dome and the base that arise as an undesigned extra feature. These are called spandrels. They could be ignored, and simply covered, but are often used to place additional decorations - paintings or statues. Gould proposes that such 'exaptions' are commonly seen also in organisms, in which a feature that may have developed randomly, or as an unavoidable result of the development of some other feature (like spandrels), are made to serve some useful purpose that may increase the fitness, but may not have been part of the original response to the challenge. Again, for reasons not very clear to me, Dennett is against this idea, calling it a 'skyhook', which in his language is a curse word. The idea of spandrels is attractive to me as a possible explanation for the evolution of intelligence and consciousness and culture. Clearly these are not required for mere survival, for, as I pointed out earlier, cockroaches survive better that humans. So maybe they are just spandrels. The issue of Nature dated 8/8/2013 (vol 500, No. 7461) has a research report that describes an exaption. A computational analysis shows that a metabolic network adapted to process and use one type of carbon source could be exapted, without change, to process other sources as well. Dennett, however, believes that the 'Gospel of Darwin according to Dennett', the one that has only cranes and no skyhooks, only allows mutations that specifically increase the fitness.
Both 'skyhooks' and 'cranes' could play a role in pushing evolution forward. Some of the present day features could have arisen one way, and others, the other way. Some speciation could be due to linear cranes on crane on cranes, and others due to non-linear cranes - i.e. skyhooks. A priori, and logically, there is nothing against either procedure, and neither violates the Darwinian algorithm. Future research may unearth other procedures, or may help decide between one method or another.
Dennett's book also explores the application of the algorithm to explain the development of ethics, religion, social organisation and the other special features of our peculiarly human society. He believes that the 'dangerous idea' is sufficient to lead to the development of all this complexity. In an earlier book, called 'The Mind's I', Dennett (and Douglas Hofstadter) made clear their belief in the possibility of the 'hard' version of artificial intelligence. They said that it should be possible to build a machine that would be indistinguishable from a human, not only in its actions, but in the way its 'emotions' and 'psychology' are perceived by the outside world. The reactions of such a machine to any kind of external input would not be different from those of complex human being. This in turn would mean that all our intelligence, our emotions, our creations, and our psyche are a result of complex, but nevertheless 'mere', algorithms running in the machinery of our bodies and brains, algorithms that we should be able to decipher and eventually recreate and run on the machines that we construct. In this book, Dennett first of all suggests that his bare-bones version of Darwinism, with cranes and no skyhooks, is sufficient to lead to intelligence and all the special human characteristics. Secondly, he further believes that application of the dangerous algorithm can also lead to human social organisation, religion, ethics, arts and culture - perhaps wars and slavery and that sort of thing as well.
I believe that there is some truth in this. The basic algorithm can be used to explain, for example, how certain social systems arise as most favoured ones from a variety of different possibilities. For instance, a Darwinian process, as described by Dennett, may be responsible for the kind of political system we have now in India. Politicians need money to win elections - the more money you have, the better your chances of winning. This leads to a system where, during elections money flows downwards from the parties and the candidates to the voters. In between elections, money will flow upwards, from the people to the police and officers and petty politicians and then on to the parties and the party leaders. Obviously there are 'transaction' costs in the system, and the intermediaries becomes richer both when the money flows up, as well as when it flows down. Equally obviously this leads to corruption at all levels. But finally we get a stable system of governance, though not a very efficient one, nor one that actually implements all the 'truths' it proclaims. Hegelian and Marxist arguments regarding dialectics and 'historical processes' are also, at their core, Darwinian.
The so-called 'genetic algorithms' are another expression of Darwinian methods, coded into computer programs and used for optimization in science, technology, industry and commerce. There are also evolutionary methods used in chemistry and molecular biology to create new molecules. However, these are examples of reverse engineering, and not really a natural progression of Darwin's idea into realms far from nature. In fact many of these algorithms are only approximations to the procedure laid out in the beginning of the essay. In particular, decisions regarding how to generate replicates in each succeeding iteration, and what fitness functions to apply, are made solely in order to get the required results faster, with no reference to the situation obtaining in nature.
Despite these well-known extensions of Darwinian processes to various aspects in human society, some of which are discussed in the book, Dennett does not support the ugly, extreme versions of social Darwinism, which are mostly scientifically false and philosophically sterile. Such versions as may be found in some of Nietzsche's writings are tautological. (Something survives because it is good. But why is it good? Because it survives.) Dennett makes a more limited point that an upward application of the 'dangerous' idea should be able to explain the need for ethics and social organisation, without having to invoke God as a skyhook. This sounds alright. Less acceptable is his strident claim that his version of the theory, and only his version, would explain the existence of all of biology from molecules and cells, all the way to societies and ethics.
When we consider the application of Darwinian ideas to prebiotic evolution, i.e. to explain the origin of living systems from among non-living matter, it is clear from many, many experiments, and the theories built to explain them, that conditions on early earth were suitable to create most of the basic building blocks of the current biological systems by random chemical reactions, in 'some warm little pond'. These 'Lego' pieces could come together, again at random, to build a variety of systems, among them a self-replicator. Copies of this would obviously multiply, and the Darwinian process could start - variation, replication, natural selection. The experiments and the theories do not establish that this is how it actually happened, but they do point to a way, or ways, by which life could arise naturally, without the need for any supernatural intervention. It would pertinent to repeat here the core idea of the Darwinian process. The variation occurs in the molecules at random, without reference to what would produce greater fitness. Selection occurs among the random variants. Information about which one of the variants has greater fitness does not flow back to the machinery creating the random variants. In other words, information flows from the genotype to the phenotype, and never the other round. The Darwinian process is itself blind, and there is no 'learning mechanism' at that level. This principle was firmly established by Francis Crick (who, together with Watson, Wilkins and Franklin, discovered the structure of DNA) in modern molecular biology when he enunciated it as 'Information flows from DNA to RNA to Protein, and never the other way around' He called it the 'Central Dogma of Molecular Biology' thereby drawing attention to the fact that it is stated in the nature of an axiom or principle, and not as an experimentally established fact. However, there has been as yet no experiment which can be interpreted as violative of this principle, in all of biology and biotechnology before and since.
Dennett's writing style is a bit stodgy. He tries often to lighten the text with jokes. But these are mostly snide attacks on some of his peers, and serve only to irritate. In the first half of the book, he has the annoying habit of repeatedly mentioning some topic and promising to treat it in detail later, or referring to some other book of his, where he implies he has irrefutably proved his point. Maybe he does give a more detailed of the point elsewhere, either in this book or in some other, but who can keep count? The final impression I get from the book is of a commentator on evolution who is on the correct side of the Darwinian/aDarwinian divide, but is wannabe deep thinker, expressing his frustration with the establishment by taking potshots at the more respected analysts.
However, this is a good and well-written book, well worth reading and thinking about, and following up on.
As far as it goes, this is alright, and fits in exactly with what I know of the rather subtle theory of evolution propounded by Darwin. The theory needs reiteration, because the simplified, Twitter-style 'handle' that is often used to describe it - 'survival of the fittest' - does not sufficiently protect the theory from misrepresentations and accusations of circular argument. Though the statements in paragraph above are deliberately not formulated as specific to biological systems, Darwin, of course, devised his theory to explain the origin of the myriad species of life forms on earth. Restated in the light of subsequent discoveries in genetics and molecular biology, the theory could start with DNA undergoing random mutations, one of which could increase the 'fitness' of the parent organism to exist and procreate in its environment. This results in a greater number of replicates of the fitter mutant in the succeeding generations. When this algorithm, as Dennet calls it, is iterated over millions of generations, it leads eventually to today's billions of different species, bacteria and bugs and worms and frogs and birds and cockroaches and snakes and whales and sharks and apes and humans and elephants and ...., all starting from very elementary life forms, i.e. single celled organisms. Or something even simpler, but here we go into the somewhat murky realms of prebiotic evolution. More on this later, trying to examine whether the idea can actually be applied 'downwards', towards molecules and atoms and subatomic particles - and 'upwards', to social organisation, to human self awareness and consciousness, and to the arts, artifacts and creativity. Dennet appears to think it can, and hence gives it the appellation 'dangerous'.
But the theory as stated above is open to an unwarranted inference, which must here be specifically denied. Evolution does not lead necessarily to life forms that are, in any absolute sense, 'better' with each succeeding generation. The mutant organism is able to multiply better - and it need to do that only marginally better - than the non mutants; this is sufficient to ensure its survival with a slightly greater probability. Many, many such mutations leads to speciation, but the new species so generated cannot be compared to each other on any absolute moral or intellectual grounds to chose one as a higher life form, and the other as a lower. Consider that all - ALL - life forms extant today have evolved from the same primordial single celled creature. Clearly the meanest bacteria we may identify today have evolved - become 'better and better' - over the same period of approximately 4 billions of years, taking as long to reach their current forms as the greatest humans. Thus in evolutionary terms, the Tree of Life does not necessarily reach to greater and greater intellectual or moral heights, becoming narrower as it grows, with humans at the very tip. It spreads as it grows, and though many branches die out (dinosaurs, for example) others are formed, until now, at the very top, we have all these billions of species, all equally evolved, all having gone with equal success through the various fitness filters. (The upward direction in the Tree of Life corresponds, of course to the Arrow of Time, with the very top representing the present day).
In fact, a tree is not the correct metaphor. In the light of what we know about 'jumping genes' and horizontal transfer of genetic information, even from bacteria to the 'higher' organisms, it would be more correct to represent the relationships between the species as a network, the branches of the tree not growing isolated from one another, but establishing contacts with other branches even after a considerable amount of evolutionary time. However, the horizontal connections are, at this point of time, not known to be as strong or extensive as the vertical ones.
A possible misunderstanding about the nature of evolution also arises from the apparent requirement of greater 'fitness' for each succeeding generation. We may ask - fitness for (or to) what? 'Fitness to (or for) the environment' is the obvious answer. But note firstly that environment does not remain the same with time or with geography. While allopatric speciation (i.e. different species arising in different geographies) may be an indication of the variation of the requisite fitness with geography, how do we explain sympatric speciation (different species arising in the same geography)? Even the smallest micro-environments (a small pond or a puddle, for example, or a small grove of trees) are populated by numbers of different species, all of them having evolved over the same amount of time, and all of them equally fit for the particular environment. The theory of evolution, of course, accommodates this easily by describing how different species occupy different niches within the same environment, or micro-environment, and how mutations which rendered the organism less fit in one geography may be adapted to make it more fit when it moves to a different environment. But note that there are many equally successful, and therefore equally good, ways for an organism to speciate in response to the challenges of a particular environment. There is no absolute scale on which to measure one way as somehow better than another, morally or ethically. On these terms, cockroaches are as 'good' as humans, perhaps better, for, as a species, they have survived longer.
A second point to note in the context of sympatric evolution is the idea of 'neutral drift' proposed by Kimura. Here the mutations, which of course occur randomly, have no effect on the fitness of the individual, neither good or bad. Speciation occurs simply by a random drift of the genes from a set corresponding to one species to that corresponding to another, both with equal fitness values, and passing through stages which also do not affect the fitness. Of course, mutations which improve the fitness would be selected for, while those that decrease it (by far the largest number of individual mutations) would be selected against. But many that survive and carry on to subsequent generations would have no effect. This idea, too, like the ones above, does not give any special moral or ethical stature to any one species.
The common feature of all the above arguments (and there are many more, all within the broad umbrella of the theory of evolution originally stated and established by Darwin, and many fiercely contested among scientists) is that we need not postulate any intelligent designer, commonly called God, superior to all life forms, who made the species. Variation, replication and natural selection are sufficient to generate the present day biosphere. (To digress a bit, there are those who claim that, while God may not have actually made the species, he may have made the rules, or the algorithms, that make the species. There is, of course, a clear and logical refutation of this, but that's an argument for another day.)
Dennett pushes this idea right from the beginning, and makes it clear that when he is critical of one or another theory of evolutionary science, he is not speaking up for religion, or for creationism, or for God. He casts his lot firmly among the atheists, and the one writer on evolution he consistently speaks of approvingly is Richard Dawkins. He is less charitable to many others, and is specially critical of Stephen Jay Gould and Noam Chomsky, seeming at times to have written the book just to dis the two.
Stephen Gould is one my favourite writers on biological topics. His writings are immensely popular and influential among thinking laymen. Some of his essays may be superficially read as being dismissive of Darwinism, and though he himself has always spoken out against creationism, American proponents of 'equal time' in the school syllabus for the Biblical version of creation have used his writings to imply that all is not well with Darwinism. Dennett allows that Gould is not a supporter of an a-Darwinian explanation of creation, but attacks at least two of the main modifications the latter has suggested to the basic theory. One is Gould's contribution to the debate on gradualism versus catastrophism. Simply put, on one side are those who believe that small changes, very small changes, sieved through the process of replication and natural selection, gradually and incrementally lead, over the eons, to speciation. On the other side are those that claim that evolution occurs in sudden and (geologically) rapid spurts that intersperse long, generally quiescent eons, during which little speciation occurs. Gould is on this side and calls his own version of this 'punctuated equilibrium'. He expounds this idea very well in his book 'Wonderful Life'. Dennett, for reasons which are not very clear to me from his book, appears to consider this against the laws of physics. Such an idea, he claims, is akin to postulating what he calls a 'skyhook', an mysterious and unknown device that somehow pushes evolution forward. This is wrong, he says, unscientific, and importantly, unnecessary. The advances in evolution are instead helped on by 'cranes', small changes that make an organism a little better. I suppose an example of cranes, and cranes upon cranes, and so on, leading to complex structures is the description of a possible pathway to the development of an animal eye in 'The Blind Watchmaker' by Richard Dawkins. Dawkins talks about a mutation leading to a primeval eye consisting of just a few cells a little more sensitive to light than the others, which would help the organism with that mutation move in the direction where there is more food (or less predation), and this slowly developing, over hundreds and thousands of generations, into a proper eye.
But there is no specific evidence against rapid changes, and we know from the study of non-linear systems in physics that sudden and large changes in a system could arise from a small change in the input (as in weather systems, for example). Thus there is nothing wrong, scientifically, in postulating such 'skyhooks'. The sudden disappearance of dinosaurs, over a geologically insignificant period of a few millions of years some 65 million years ago is an example of a rapid turn in the course of evolution, though this is thought to have been triggered by the impact of a large meteroite, not just a 'small input'. Another example of a so-called 'skyhook' postulate that invites Dennett's disparagement is Noam Chomsky's idea that the human anatomy and brain is hard-wired for the faculty of language, as in no other primate, and that this faculty probably arose by some sudden and specific developments (Chomsky doesn't actually say genetic mutations, but doesn't deny them either) maybe a few hundred thousand years ago, when the human line diverged from the other apes. Dennett laughs this off, and claims that slow changes by the basic Darwinian algorithm should be sufficient to lead to language, and further to human culture.
Dennett also takes up cudgels against another proposal made by Gould. Not all features seen in living systems are adaptations that increase the fitness of the organism, said Gould. In many medieval buildings, when a circular dome is placed on a base which is square-shaped, there are roughly triangular portions between the dome and the base that arise as an undesigned extra feature. These are called spandrels. They could be ignored, and simply covered, but are often used to place additional decorations - paintings or statues. Gould proposes that such 'exaptions' are commonly seen also in organisms, in which a feature that may have developed randomly, or as an unavoidable result of the development of some other feature (like spandrels), are made to serve some useful purpose that may increase the fitness, but may not have been part of the original response to the challenge. Again, for reasons not very clear to me, Dennett is against this idea, calling it a 'skyhook', which in his language is a curse word. The idea of spandrels is attractive to me as a possible explanation for the evolution of intelligence and consciousness and culture. Clearly these are not required for mere survival, for, as I pointed out earlier, cockroaches survive better that humans. So maybe they are just spandrels. The issue of Nature dated 8/8/2013 (vol 500, No. 7461) has a research report that describes an exaption. A computational analysis shows that a metabolic network adapted to process and use one type of carbon source could be exapted, without change, to process other sources as well. Dennett, however, believes that the 'Gospel of Darwin according to Dennett', the one that has only cranes and no skyhooks, only allows mutations that specifically increase the fitness.
Both 'skyhooks' and 'cranes' could play a role in pushing evolution forward. Some of the present day features could have arisen one way, and others, the other way. Some speciation could be due to linear cranes on crane on cranes, and others due to non-linear cranes - i.e. skyhooks. A priori, and logically, there is nothing against either procedure, and neither violates the Darwinian algorithm. Future research may unearth other procedures, or may help decide between one method or another.
Dennett's book also explores the application of the algorithm to explain the development of ethics, religion, social organisation and the other special features of our peculiarly human society. He believes that the 'dangerous idea' is sufficient to lead to the development of all this complexity. In an earlier book, called 'The Mind's I', Dennett (and Douglas Hofstadter) made clear their belief in the possibility of the 'hard' version of artificial intelligence. They said that it should be possible to build a machine that would be indistinguishable from a human, not only in its actions, but in the way its 'emotions' and 'psychology' are perceived by the outside world. The reactions of such a machine to any kind of external input would not be different from those of complex human being. This in turn would mean that all our intelligence, our emotions, our creations, and our psyche are a result of complex, but nevertheless 'mere', algorithms running in the machinery of our bodies and brains, algorithms that we should be able to decipher and eventually recreate and run on the machines that we construct. In this book, Dennett first of all suggests that his bare-bones version of Darwinism, with cranes and no skyhooks, is sufficient to lead to intelligence and all the special human characteristics. Secondly, he further believes that application of the dangerous algorithm can also lead to human social organisation, religion, ethics, arts and culture - perhaps wars and slavery and that sort of thing as well.
I believe that there is some truth in this. The basic algorithm can be used to explain, for example, how certain social systems arise as most favoured ones from a variety of different possibilities. For instance, a Darwinian process, as described by Dennett, may be responsible for the kind of political system we have now in India. Politicians need money to win elections - the more money you have, the better your chances of winning. This leads to a system where, during elections money flows downwards from the parties and the candidates to the voters. In between elections, money will flow upwards, from the people to the police and officers and petty politicians and then on to the parties and the party leaders. Obviously there are 'transaction' costs in the system, and the intermediaries becomes richer both when the money flows up, as well as when it flows down. Equally obviously this leads to corruption at all levels. But finally we get a stable system of governance, though not a very efficient one, nor one that actually implements all the 'truths' it proclaims. Hegelian and Marxist arguments regarding dialectics and 'historical processes' are also, at their core, Darwinian.
The so-called 'genetic algorithms' are another expression of Darwinian methods, coded into computer programs and used for optimization in science, technology, industry and commerce. There are also evolutionary methods used in chemistry and molecular biology to create new molecules. However, these are examples of reverse engineering, and not really a natural progression of Darwin's idea into realms far from nature. In fact many of these algorithms are only approximations to the procedure laid out in the beginning of the essay. In particular, decisions regarding how to generate replicates in each succeeding iteration, and what fitness functions to apply, are made solely in order to get the required results faster, with no reference to the situation obtaining in nature.
Despite these well-known extensions of Darwinian processes to various aspects in human society, some of which are discussed in the book, Dennett does not support the ugly, extreme versions of social Darwinism, which are mostly scientifically false and philosophically sterile. Such versions as may be found in some of Nietzsche's writings are tautological. (Something survives because it is good. But why is it good? Because it survives.) Dennett makes a more limited point that an upward application of the 'dangerous' idea should be able to explain the need for ethics and social organisation, without having to invoke God as a skyhook. This sounds alright. Less acceptable is his strident claim that his version of the theory, and only his version, would explain the existence of all of biology from molecules and cells, all the way to societies and ethics.
When we consider the application of Darwinian ideas to prebiotic evolution, i.e. to explain the origin of living systems from among non-living matter, it is clear from many, many experiments, and the theories built to explain them, that conditions on early earth were suitable to create most of the basic building blocks of the current biological systems by random chemical reactions, in 'some warm little pond'. These 'Lego' pieces could come together, again at random, to build a variety of systems, among them a self-replicator. Copies of this would obviously multiply, and the Darwinian process could start - variation, replication, natural selection. The experiments and the theories do not establish that this is how it actually happened, but they do point to a way, or ways, by which life could arise naturally, without the need for any supernatural intervention. It would pertinent to repeat here the core idea of the Darwinian process. The variation occurs in the molecules at random, without reference to what would produce greater fitness. Selection occurs among the random variants. Information about which one of the variants has greater fitness does not flow back to the machinery creating the random variants. In other words, information flows from the genotype to the phenotype, and never the other round. The Darwinian process is itself blind, and there is no 'learning mechanism' at that level. This principle was firmly established by Francis Crick (who, together with Watson, Wilkins and Franklin, discovered the structure of DNA) in modern molecular biology when he enunciated it as 'Information flows from DNA to RNA to Protein, and never the other way around' He called it the 'Central Dogma of Molecular Biology' thereby drawing attention to the fact that it is stated in the nature of an axiom or principle, and not as an experimentally established fact. However, there has been as yet no experiment which can be interpreted as violative of this principle, in all of biology and biotechnology before and since.
Dennett's writing style is a bit stodgy. He tries often to lighten the text with jokes. But these are mostly snide attacks on some of his peers, and serve only to irritate. In the first half of the book, he has the annoying habit of repeatedly mentioning some topic and promising to treat it in detail later, or referring to some other book of his, where he implies he has irrefutably proved his point. Maybe he does give a more detailed of the point elsewhere, either in this book or in some other, but who can keep count? The final impression I get from the book is of a commentator on evolution who is on the correct side of the Darwinian/aDarwinian divide, but is wannabe deep thinker, expressing his frustration with the establishment by taking potshots at the more respected analysts.
However, this is a good and well-written book, well worth reading and thinking about, and following up on.
