Terren Suydam: “The first is that one has to adopt the group-selection stance.”
(Technical jargon nitpick.)
In studying evolutionary biology, “group-selection” has a specific meaning, an individual sacrifices its own fitness in order to improve the group fitness. I.e., individual loss for a group gain. E.g., suppose you have a species that consists of many small family groups. Suppose a mutation produces a self-sacrificing individual in one of the groups. His fitness is slightly lower but his family group fitness is higher. His group tends to grow faster than other groups. So his group produces more splinter groups, some of which will have his alleles. Within any one group his allele tends to die out, but the overall population frequency of the allele increases due to the increased number of splinter groups containing the allele. This is an example of group-selection.
Much more common is cooperation that doesn’t lower the individual’s fitness. In this case it is win-win, individual gain and group gain. Symbiosis is an example where the cooperation is between different species. Both individuals gain so it is not an example of group-selection.
There are a few known examples of group-selection but they tend to be the rare exception, not the rule. Often something appears to be group-selection but on closer analysis turns out to be regular selection. E.g., suppose a hunter shares his meat with the tribe. He isn’t lowering his fitness because he already has enough meat for himself. He is publicly displaying his prowess as a food provider which increases his mating success. Thus his generosity directly improves his fitness. His generosity is a fitness increasing status display.
Cooperation can and usually does arise through regular selfish selection.
Terren Suydam: “The first is that one has to adopt the group-selection stance.”
(Technical jargon nitpick.)
In studying evolutionary biology, “group-selection” has a specific meaning, an individual sacrifices its own fitness in order to improve the group fitness. I.e., individual loss for a group gain. E.g., suppose you have a species that consists of many small family groups. Suppose a mutation produces a self-sacrificing individual in one of the groups. His fitness is slightly lower but his family group fitness is higher. His group tends to grow faster than other groups. So his group produces more splinter groups, some of which will have his alleles. Within any one group his allele tends to die out, but the overall population frequency of the allele increases due to the increased number of splinter groups containing the allele. This is an example of group-selection.
Much more common is cooperation that doesn’t lower the individual’s fitness. In this case it is win-win, individual gain and group gain. Symbiosis is an example where the cooperation is between different species. Both individuals gain so it is not an example of group-selection.
There are a few known examples of group-selection but they tend to be the rare exception, not the rule. Often something appears to be group-selection but on closer analysis turns out to be regular selection. E.g., suppose a hunter shares his meat with the tribe. He isn’t lowering his fitness because he already has enough meat for himself. He is publicly displaying his prowess as a food provider which increases his mating success. Thus his generosity directly improves his fitness. His generosity is a fitness increasing status display.
Cooperation can and usually does arise through regular selfish selection.
(I see EY also noted this.)