I don't know how it is in CIV 6 but in CIV 5 the more population one has the more he or she becomes advanced. However, is it really how it is in reality? In that case shouldn't India, Pakistan, Nigeria, and Brazil be one of the leading countries? I believe the reason why certain civilizations advance faster then others is because of the resources they have. The more resources one has the more faster one should advance. One of the crucial resources that helps advance the nation are horses. Because of them civs were able to advance much faster then others. They were like trucks back in the day, bringing goods from one point to another. How can India, Africa and Americas advance faster if they don't have any horses? Of course civs like Europe will advance much faster if they have woods, crops, and animal husbandry. Animal husbandry should be one of the best if not the best resources in the game. Another example how can one excel in desert conditions like middle east? How can they builds ships and with what? Does more population really generates more science?