Religions with an emphasis on dieties you cannot sense, and an afterlife that represents a complete divorce from the concrete, was evidence of the capacity of people to engage in abstract thought. Insofar as this is consistent and widespread enough to turn into traditional burial practices throughout a society it is an advanced stage in intellectual growth as a species. So is the capacity to give and communicate meaning through symbols( art and hierogryphics) , the ability to draw a map in the dirt, or do simple math etc. We no longer draw maps with a stick. We interpret a screen with moving dots on Mapquest instead. And we no longer use hierogryphics. We have an alphabet based on sound rather than sight symbots. That's not because we couldn't do it the 'old way'. There are tons of ways we prove that we handle and exploit abstract thought as a species. Losing faith in religion or and afterlife as an answer to questions, says absolutely nothing about us as a species losing our ability to think and understand those concepts.