I had the radio on while heading off to choir practice this evening. Sr. Helena or Sr. Susan had left it on a Catholic station, so I listened to a pre-recorded call-in show--one of those shows with a different guest behind the mike each time. The topic was "the New Age," something that of its very nature is pretty vague, but this presenter seemed to see New Age philosophy (is there such a thing?) or spirituality behind anything that did not originate with explicit Divine Revelation. Not only did she dismiss these things as inappropriate for Christian believers (which they may well be), she indicated that they were all the work of the devil, and if you didn't agree, then maybe you were "bound" by the powers of darkness. And if you didn't like that, well, she would cite the Catechism or a Church document which did not say that, exactly, but which she interpreted to say that, and so you would just have to resign yourself to what she was saying.
She applied this not only to the syncretistic religious practices that clearly are New Age, but even to ancient religions and their various expressions, not admitting that there was anything redeemable in them that could be Christianized or adapted harmlessly by Christians. (She explicitly ruled out any possibility of elements of the Hindu culture being Christianized, and she had her doubts about accupuncture, too, since it is inspired by a non-Christian understanding of human life and destiny.)
I'm certainly glad that the missionaries to my Celtic ancestors didn't have that understanding of evangelization. They didn't seem to have a problem with recognizing the "seeds of the Gospel" in the pagan culture of Ireland, and capitalizing on them to allow the Gospel to take root in a new culture. That new culture became so strongly committed to the Gospel that its land was called the Isle of Saints, and much of what we Americans assume is "Catholic culture" pure and simple is really the Celtic-flavored version.
It's a simple matter of the Incarnation. God became man in a specific culture and people. The Gospel, too, can become "incarnate" in different cultures without compromising its divine integrity.
The document "Ad Gentes" (on the Missionary Activity of the Church) makes it very clear that in evangeling cultures, we cannot expect to purge all elements of a native culture and then train the people to take on a new culture (no matter how venerable). No, their own culture is to be "redeemed" by the Gospel: "Whatever truth and grace are to be found among the nations, as a sort of secret presence of God....whatever good is found to be sown in the hearts and minds of men, or in the rites and cultures peculiar to various peoples, not only is not lost, but is healed, uplifted, and perfected for the glory of God, the shame of the demon, and the bliss of men."
It would be easier the other way around, but it's not the way God has chosen.
At least, that's what the Church teaches.