"People tend to look out for people of like faith, as in churches, and that support can make them stronger, thus improving the chances that they will live long

"People tend to look out for people of like faith, as in churches, and that support can make them stronger, thus improving the chances that they will live long enough to see their genes passed along." Its kind of a stretch as an argument. Common identity is what brings people together, thus enabling social support structures. If people are brought together by ideas, true or not, its because those ideas are core to identity. Ideas themselves have their own selection criteria for being passed on - http://pespmc1.vub.ac.be/MEMSELC.HTML http://pespmc1.vub.ac.be/MEMSELC.HTML If I were to re-phrase the thesis, it would be something like this - 'Humans have the ability to infer cause/effect relationships based on the most relevant information available. Often, the perceived relevancy of ideas is heavily influenced by ideas that are held to be true in present cultural belief system. Over time, as more information is available to the culture, there may be a disparity between observed information (facts) and cultural ideas (beliefs). In this scenario, relevancy of ideas will still be influenced by cultural ideas, sometimes to the point of necessitating the dismissal of observed information.'