Joseph Campbell was an expert in world mythology who adopted a lot of ideas of Jung in his analysis of myths. His works make very interesting reading.
Campbell treated the dogmas as Christianity as myths which more or less just reflect man’s state of conciousness towards the Absolute, probably an idea he got from reading about Eastern religions and philosophies, which regard the world of experience as illusory and a veil over the Absolute. For Campbell, myths around the world all try to raise the human mind past the veil of reality into the Absolute itself. To him, all pagan and religious mythologies are equivalent in terms of being able to do this. And also to him, the God of monotheism is a personal symbol for an impersonal Absolute.
Christians can’t really accept that God is impersonal; the Pope pointed out in Deus Caritas Est while we believe in the God of the Philosophers, we also believe in the loving and active God of the Bible. What other religions conceive to be impersonal and changless (i.e. nirvana) is for us an active and living reality. God’s essence or unconditioned being does not change, but God nevertheless still acts in such a way towards us that God is not merely a passive void beyond the symbol but is also an active reality who reaches down and out to us to bring us to salvation. So Campbell’s ideas are not acceptable if they simply see all religions as just symbols for raising the mind to an impersonal Absolute behind appearances. But, they do shed light on the common human quest for God.