In Chapter 13, Dawkins claims that the gene has some uneasy tension with letting the gene be the unit of evolution. He thinks that accepting this theory might lead some people to question their sense of agency. Luckily, he has written a whole other book on this subject. Genes might be the unit of selection, but they have a shared fate in the individual. Genes can cheat too, by creating a phenotype that is bad for the individual, but by hurting the individual and other genes it will eventually lose out because its not an Evolutionarily Stable Strategy. Parasitism is not an ESS either. Eventually, Dawkins hypothesizes that all parasitic relationships will become symbiotic or die out. Otherwise, they would not be stable. Finally, Dawkins argues that a genes effects should not be measured by the effect they have on the individual, but rather by the effects they have on every individual they are found within. Genes should be judged on its total effects on the world.