Taken directly from the Quakers in Leeds Website (the emphasis in bold is mine):
Quaker thought and practice has always refused to be contained in credal formulas or systems of belief. We don’t offer neat creeds or doctrine. Instead, we try to help each other work out how we should live. All people are welcome and accepted at a Quaker meeting.
Quakers seek religious truth in inner experience and everyday life, rather than authority, ritual and ceremony.
Quakerism is not itself a religion nor is it, any longer, entirely accurate to describe it as a Christian denomination because many of our followers find no purpose in affirming or denying traditional Christian beliefs about God or Christ.
The Quakers are probably best described by their official title; we are a “Religious Society of Friends”.
I was led to this site by a post on Raking Sand, Leeds Trinity University staff and students raking over religion and philosophy titled Considerations of the insider/outsider problem in a Quaker meeting.