The Selfish Gene Theory Philosophy Essay

Dawkins proposed that the individual is merely a carrier for genes (the replicators), and that the body acts as a pre-coded tool by which these genes propagate themselves, adapting over time to suit the needs of their environment. Midgely’s argument hinges around a misinterpretation of Dawkins’ theory on several levels. Mistakenly projecting the nature of genetic selection to its implications for the human mind is a recurrent theme in her article ‘Gene Juggling.’ She adopts a view that, if genes are selfish replicators selected for their own ability to survive in the gene pool, the nature of the human mind must, by extension, also be selfish. However, genes which are selected for their ability to survive may well ultimately code for altruistic behaviour at the level of the individual, evidence for which will be discussed through the course of this essay. In some respects she even takes a literal interpretation (as implied in the titular quote), implying that the gene is consciously selfish, which is of course absurd, and doesn’t reflect the intended meaning of the theory.

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Midgely (1979) stated:

(Dawkins) central point is that the emotional nature of man is exclusively self-interested, and he argues this by claiming that all emotional nature is soaˆ¦ he resorts to arguing from speculations about the emotional nature of genes, which he treats as the source and archetype of all emotional nature.

– Gene Juggling, (1979) pp- 445

This is a misapplication of the theory because it mistakenly shifts the focus from the genetic level to the individual level. The quote represents an invalid syllogistic form, i.e. an incorrect propositional construction: She assumes that because genes which are subject to the laws of evolution code for organisms, and the mechanisms of evolution select for genes which pursue their own interest, (in other words, genes which are ‘selfish’), the emotional nature of man must therefore also be selfish. This is a misconception, and a false leap of logic – the genetic environment is altogether different from the macroscopic environment. There is evidence, such as game theory ESS models and eusocial insect studies, that the nature of genes can give rise to altruistic behaviour at the level of the organism, or individual, as explained repeatedly in the selfish gene. Any behaviour – whether altruistic or selfish – can only come to pass if it ultimately benefits the replicators, although at the level of the individual, phenotypic effects coded for by genes interact with the numerous conditions of the environment, for which the permutations are nearly infinite (Woltereck, 1909) in a norm of reaction. Therefore, the possible phenotype of any organism with a given genotype is impossible to tell – there will be environments in which altruistic behaviour is the best strategy for survival, and environments where self interested behaviour is the optimum, and everything in between. The optimal strategy for survival, on any level of the phenotype (morphology, physiology, behaviour) will vary as much as the permutations of environmental states. Therefore, Midgley’s assertion that because genes act selfishly, the emotional state of man must be selfish, is fallacious – the genotype may well interact with the environment to produce altruistic behaviour and non-selfish emotion.

With regard to apparent altruism in animals, (Hamilton, 1972) postulated that these behaviours may have evolved over time because they serve to increase genetic fitness. In most species (haplodiploids being an exception) the genetic relatedness between parent and child, as well as between siblings, is 0.5. Hamilton suggested that altruistic behaviour would be proportionate to genetic relatedness, with risk also taken into account. The formula for this is: rB>C. For instance, in a situation with equal risk to both the actor and recipient(s), ceteris paribus, an organism would only act to save 2 or more siblings, because that’s the point at which the genetic fitness would see a net increase as a result of the action. This behaviour doesn’t make the gene(s) which code for it inherently selfish or altruistic. It’s just the logical evolutionary outcome of genes which are selected for their ability to ensure their own future survival and spread in the genepool. Interestingly, at the level of the individual this genetically selfish motivation is manifested in what we would see as altruistic behaviour.

Empirical evidence for this theory comes from analysing the behaviour of haplodiploid species, which differ significantly to us in genetic relatedness of kin. In most eusocial insect species, for instance the hymenoptera, the relatedness between mother and daughter, as well as mother and son, is 0.5. However, between sister and sister it is 0.75, and between sister and brother it is 0.25. (Hamilton, 1967). Kin selection theory would suggest that, because of this genetic asymmetry, the sex ratio equilibrium should change depending on which agent is in control, due to the conflict of interest in which sex to rear. Female workers would want a ratio of 3:1 sisters:brothers, because they share more genes with sisters. The queen would want a sex ratio of 1:1, because the genetic relatedness between her and her daughter/son is 0.5 in both cases. (Trivers and Hare, 1976) found that in most of these species, the ratio of investment is roughly 3:1, as the workers are mostly responsible for raising the offspring. However there is some variability, for example in some cases the queen masks the scent of her eggs so that the workers cannot tell which is female or male, in order to deceive them into raising the larvae with an equal ratio of parental investment. This provides compelling evidence for the selfish gene theory, as the insects are engaging in parental investment behaviours which reflect their genetic stake in the offspring – maximising their own genes likelihood of survival.

John Maynard-Smith (1973) uses the concept of the evolutionary stable strategy (a key idea in game theory) to explain competition between and within species. A strategy which, during iterated ‘games’ over time, cannot be invaded by new strategies, is considered an ESS. For example, there is a classic game in which either side can ‘defect’ or ‘cooperate’ – known as the ‘Prisoners’ Dilemma’ (Flood and Dresher, 1950), where the reward for player defecting, opponent cooperating > mutual cooperation > mutual defection > player cooperating, opponent defecting. In this case, if there is just one game between players, then the logical move is to defect, because this will maximise your reward regardless of the other player’s move. However, if the game is iterated, i.e. repeated over time, then there is opportunity for ESS’s to evolve. Axelrod simulated this in a computer program with numerous strategies, and found that ‘tit for tat’ won, with the most ‘reward points’ accumulated in the tournament. The strategy specifies ‘cooperate unless opponent defects, in which case retaliate by defecting the next turn’. Tit for tat is also forgiving – if an opponent breaks a cycle of defections by cooperating, it will go back to cooperating also.

The success of a strategy depends on the types of strategies it faces, and the proportion of each relative to the others. Over time evolutionary stable strategies will reach an equilibrium point, where oscillations between the success of strategies will be minimal and due to chance. For instance, if an ‘always defect’ strategy were to randomly arise in a group of tit for tats, it would quickly be retaliated against and driven to extinction, preserving the equilibrium. In nature, particularly in animals with grouped social structures and territories, the conditions under which a tit for tat strategy would be successful are present. It seems logical that animals in regular contact with each other, with iterated ‘games’ between the same participants, would have evolved to follow the strategy. It could be argued that mutual grooming, for example, is an example of tit for tat in nature, where both animals are ‘cooperating’. If one were to stop, the other would retaliate by stopping also. This grooming behaviour is common in a multitude of species, from mammals to birds.

In terms of the selfish gene theory, Dawkins proposed that the gene pool is an evolutionary environment, in which ‘good’ genes (those which survive in the gene pool) are selected for. Therefore, the gene pool can be seen as an “Evolutionary stable set of genes”. Through random mutations in DNA, new genes will enter the environment, and most will be quickly selected against. However those that are beneficial to the organisms that carry them will spread throughout the gene pool, and shift the evolutionary stable set towards a new equilibrium – these shifts represent the process of evolution. If a gene arose which altruistically increased the welfare of its alleles, for this very reason it would become extinct in the gene pool after a short while. Therefore, in nature we can only

expect to see ‘selfish’ genes which are best at ensuring their own survival in relation to their alleles – like an ESS, evolution will only allow the survival of genes which are resistant to the invasion from others in the gene pool, otherwise they will become extinct. ‘Selfish’ isn’t used in a subjective, emotional sense – it’s simply the type of unit we would expect to see as a result of the evolutionary process. Midgleys ‘gene juggling’ article seemed to imply that Dawkins used the term in an emotional capacity, which isn’t what he intended.

Considering the body of an organism as a carrier for the genes within it, these genes must have evolved to cooperate at some kind of level during early evolutionary history, nearly 4 billion years ago. Over time through replication and environmental changes genes formed ‘vessels’ i.e. animals and plants, through which they competed for permanence in the gene pool. In human DNA there are approximately 20,000-25,000 unique genes (Human Genome Project, 2003). Therefore, an individual genes environment consists of a huge number of others with which it works to code for an organism. When it comes to which are selected for and against, the genes environment is key – for example a gene that codes for a herbivorous characteristic such as a very long neck for reaching treetops, will do very poorly in the genetic environment of a carnivores body, for which the trait would be useless (Dawkins, 1976). As a result, this gene would be selected against, not because it’s bad at its job, or the job itself is a bad idea, but because the job it performs is made redundant due to its environment. This explains why we see organisms specialized for certain tasks or environments, the same principles that are applied to animals at the individual level of selection can be imposed at the genetic level.

On the other hand, lethal genes exploit their genetic environment by not exerting their effect until after the point of the organisms reproductive fertility. This effect, although detrimental, could be selected for – if an organism tends to reproduce before dying as a result of particular genes, then these lethal genes have been selected for, despite having been carried via their genetic environment (Medawar, 1952). Another theory suggests that over time the copying errors and genetic damage accumulate in an organism and eventually it dies of old age. Perhaps this can be related to Medawar’s theory, in that because old age occurs (from genetic copying damage) after the main period of reproductive success, there is no evolutionary advantage for genes that don’t deteriorate and cause the organism to eventually die, and no selective pressure against those that do. Therefore, the potential age of species remains constant. Moreover, individual selection theory can’t really account for why organisms die of old age at all – surely living longer would be selected for over the course of evolutionary history. Group selection, on the other hand, explains organisms dying as an act of altruism to conserve resources and space to preserve the species or group; however this isn’t backed by much evidence and is generally dismissed as an explanation. This leaves gene selection as the only reasonable explanation for organisms dying of old age.

Genetic crossing over during sexual reproduction involves a “reshuffling” of genes within chromasomes, during meiotic division, as the offspring inherits 50% of the parents Genes. During this division, cistrons are divided and changed, meaning each offspring is genetically unique. Statistically, the smaller the piece of genetic material, or cistron, the less likely it is to be reshuffled by crossing over, and the higher it’s copying fidelity, or lifetime over generations. A specific chromosome will have a lifespan of 1 generation, but the smaller the part (cistron) within the chromasome, the more generations it is statistically likely to survive without being chopped and changed. If ‘selfishness’ relates to the units behaviour and longevity, as a function of natural selection, then the smaller the genetic unit, the more ‘selfish’ it is.

An alternate theory of evolution is that of group selection (Wynne-Edwards, 1962) which states that instead of natural selection taking place at the level of the individual, or gene, it takes place at the level of the group, suggesting that behaviours which are detrimental to the individual organisms genes may be perpetuated given that it results in a net improvement to the fitness of the group. For example, one prediction is that organisms will regulate their birth rates in order to prevent overpopulation and consumption of resources, and it is suggested that some species adhere to hierarchies where the top animals get to mate and subordinates do not, in order to regulate population growth, observed in animals such as hens (hence the etymology of the idiom ‘pecking order’).

It is also suggested that insects such as midges gather together in displays to assess population numbers and prevent overpopulation (Wynne-Edwards). If the population is too high, resources will be spread too thin, and the overall welfare of the group will decrease. However, in light of genetic selection theory, and a lack of evidence to support this assertion, it seems unlikely that this is the case. Gathering together for population displays costs a lot of energy, and sacrificing the passing of genes through mating can’t logically be selected for, even if it does benefit the species in the long term. These behaviours can’t be part of an ESS, because they are vulnerable to attack from strategies which don’t gather and mate regardless, both saving energy and passing on genes. Because of these benefits, the individuals that take advantage of the group will be selected for and eventually increase in numbers within the system, because group selection behaviour doesn’t represent an ESS.

In conclusion, genes can be selfish insofar as to be selected for as a fundamental unit of natural selection, coding for any phenotype which will enable the organism to reproduce and therefore pass on copies of the genes themselves. ‘Colonies of genes’ which make up individual organisms seem to display the characteristics of an evolutionary environment, within which the genes must make an ESS. As such, at the level of the organism, genes may code for apparently altruistic behaviours, such as kin selection, a theory for which there is compelling evidence, but the ultimate reason for this coding at a genetic level is selfish – it is designed to increase the survival rate of genetic copies. Midgley misapplied this theory in her article, suggesting that the emotional state of man must be of a selfish nature as a result of this coding – ‘philosophic egoism’ as she called it. This is not the case, and is evident when one considers the diversity of the phenotype as an expression of genes and environment. In addition, the alternatives to genetic selection have a lack of evidence and aren’t as logically sound. Group selection, for example, only has circumstantial support, most of which can be explained by other means anyway – no one can prove that subordinate animals forego mating for the good of the species, it is far more likely that they would fight for alpha male status and mates given reasonable opportunity/odds. Furthermore, the selfish gene utilizes the same principle as individual selection, but at the most basic possible level, making it a preferred explanation to individual or group selection theories for behaviour wherever possible (Williams, 1964).