Meditation and Materialism

Many people try to approach meditation and Buddhism from a scientific materialist perspective, despite the fact that Buddhism makes explicit claims about the after life, and despite the fact that Buddhism explicitly state that it is a Wrong View to believe in materialist Annihilation. I posted the following questions rhetorically as part of an answer to another question, but it was suggested to be moved to its own question: So, are there any materialist explanations to the following? 1. Why is meditation pleasurable and helpful in a materialist world that is run based on natural selection? 2. How is the possibility of experiencing states of joy and peace and realizations through meditation possible through an evolutionary model? 3. What evolutionary advantage would make the desire to end greed, anger and selflessness such the desire to become a monastic (not reproducing and passing on your genes) occur? What are the materialist claims by **other philosophies** with regards to meditation that you have seen? For example: (Evolutionary psychology) people are driven to help others because it enhance group survival. According to the same thinking though, people are also jerks because it enhance their own survival. What are the counter arguments from Buddhism to these claims?