Chapter Chapter-by-Chapter Anaylsis of The Selfish Gene (1989 edition) - Study Guide by Richard Dawkins

Furthermore, as in the case of true ESSs, it is possible for more than one strategy to be collectively stable at the same time and this is true of the Prisoner’s Dilemma as well. Always Defect is also stable if it has already become established because no other strategy invading can do better against it. Therefore, Dawkins suggests that we treat the system as being bistable, with Always Defect being one of the stable points and Tit for Tat (or some mixture of mostly nice, retaliatory strategies) as the other. Which stable point comes to dominate the population will depend on mechanisms such as genetic kinship and clustering. Genetic kinship could be responsible for initiation of co-operation from a previously asocial state because animals of most species are likely to find themselves living close to their sisters, brothers and cousins, rather than to random members of the population. In this way, the chances of the individuals that live near you containing the same gene for Tit for Tat tendencies as you do are good and so you will all tend to benefit from mutual co-operation.

The other possible mechanism that allows reciprocal co-operation to gain a foothold in a population that is presently using ALL D is clustering. This is when mutant strategies arrive in a cluster of individuals all using the same strategy so that they form a nontrivial proportion of the interactions. For example, if Tit for Tat individuals occur in clusters then they can interact with each other more than expected from random encounters in the population at large, and hence enjoy the increased benefits of mutual co- operation. In this way, they will be able to become established as a more successful strategy and will soon reach fixation. Therefore, unrelated individuals are seen to cooperate with each other is they have a sufficiently high probability of meeting again so that they have a stake in their future interaction.

Dawkins summaries by saying that the success of non-envious, forgiving niceness (as a behaviour) depends on three factors:

1. that nature should set up circumstances that fit these games of Prisoner’s Dilemmas
2. that the shadow of the future is long (by which he means that neither "player" should know when the game is going to end)
3. that the games should be nonzero sum games (by which he means that both players can "win" if they cooperate i.e. a win for one player does not automatically mean a loss for the other).

Indeed, he points out that these conditions are commonly met around the living kingdoms and consequently the cooperative behaviour evolves.

The long reach of the gene

Throughout the entire book, Dawkins has argued that evolution in terms of selection occurs at the level of the gene and not at the level of the individual. However, this theory has always faced resistance from those who insist on asking questions about organisms, why organisms do this, why organisms do that and why organisms group themselves into societies. What Dawkins believes is that we should in fact ask why living matter (the replicators) groups itself into organisms in the first place. He asks: "Why isn’t the sea still a primordial battleground of free and independent replicators? Why did the ancient replicators club together to make, and reside in, lumbering robots, and why are those robots – individual bodies – you and me – so large and so complicated?"

Dawkins understands that many biologists find it hard to see that there is a question here at all because individuals have now evolved into a form so large and coherently purposeful. However, in this final chapter, he attempts to briefly answer these questions (although he says his detailed explanation can be found in The Extended Phenotype). He reminds us that what is important is for the replicator to survive and propagate itself into the next generation. However, now he introduces the idea that replicators survive, not only by the quality of their intrinsic properties, but also by the quality of their consequences on the world. By this he means that genes have tools that extend outside the individual body wall which can be use to manipulate other individuals for their benefit.