Why the following: "the selection pressure at the individual level tends to outweigh the pressure at the group level". Because "I had 1.8 viable offspring befo

Why the following: "the selection pressure at the individual level tends to outweigh the pressure at the group level". Because "I had 1.8 viable offspring before I died" is more fit than "I had 1.5 viable offspring before I died", no matter how you slice it. Any trait that moves an individual from the former statement to the latter makes that individual less fit, even if it benefits the group, and since the individual is less fit, that trait is less likely to be passed on, resulting (asymptotically) in more fit individuals massively outnumbering less fit ones, irrespective of the impact those individuals have on group fitness.