All philosophies and all beliefs rest on assumptions. This is widely known and accepted in the field of philosophy. These are called basic beliefs or properly basic beliefs. They are supposed to either be self-evident or incorrigible (unable to be improved or corrected). This is a staple of Classic Foundationalism but is also a part of most post-modern philosophies in some way.

 

There are two very popular critiques of Christianity:

1.)  Karl Marx saw religion as a cognitive malfunction, that religion is produced by cognitive faculties that are not functioning properly. This dysfunction is due to a sort of perversion in social structures, a social malfunction. ‘Religion is the opium of the people.’

2.)  Sigmund Freud believed that religion is a by-product of wish fulfillment. We live in a cruel, cold, meaningless world, and to make us feel better about that we imagine that there is a loving father out there who has a plan for it all. Reality is too depressing for many so they imagine a God.