Andy Gardner

“Hamilton's original contribution was to realize that indirect fitness effects impact upon the purpose of adaptation. The basic condition for natural selection to favor any trait is that the individuals who carry genes for this trait are, on average, fitter than those who do not. However, the adaptations that subsequently evolve are not designed for maximizing the individual's personal fitness, but rather her inclusive fitness, i.e., the sum of all the fitness effects that she has on all of her genetic relatives, each increment or decrement being weighted by the corresponding coefficient of genetic relatedness (Hamilton 1964). In other words, the adaptive agent remains the same as in the traditional Darwinian view (i.e., the individual organism), but the adaptive agenda is changed. This idea has subsequently been formalized by Grafen (2006), who has shown the mathematical connection between the dynamics of natural selection and an optimization program in whih the individual strives to maximize her inclusive fitness, for a wide class of models, including those that allow for social interaction between relatives.
Grafen A. 2006. Optimization of inclusive fitness. J Theor Biol 238: 541-563.
Hamilton WD. 1964. The genetical evolution of social behaviour I & II. J Theor Biol 7: 1-52.”
― Andy Gardner, From Groups to Individuals: Evolution and Emerging Individuality