Schleiermacher's religious naturalism considers religious affections as a spontaneous and ordinary experience of all humans. Confessional identity is only subsequently bestowed to the naturally produced religious experience. Confession doesn't engender religion but it only moulds its expression into a culturally determined pattern; generally, the pattern is given by the outstanding example of a particular religious leader or event. Even if expressed and cultivated according to a common example, religion remains highly particular, its variety going down until the individual level. In most cases, the difference between confessions relies on the differences between their implicit cosmological views. Progress of civilization didn't really involve a progress of the religious feeling itself, but rather a progress of its manner of expression.
Considered as the feeling of utter dependence of every finite being on the Infinite, religion necessarily embeds an attitude of absolute openness, seeing everything, including all faiths, as complementary within the all-encompassing unity. Hence, religious pluralism is not just a possible view, but it belongs to the very essence of religiosity.