In October 2006 Wilber published a new book, Integral Spirituality. Here he complements the quadrants with perspectives, from inside and from outside. A person, who is meditating, experiences himself from inside and can not see himself from outside, can not see that he is active on a certain level in the upper left quadrant, and that he knows nothing about the other three. The old wisdom traditions from hinduism, buddhism, Christianity, islam etc. cannot therefore withstand the criticism from modernity, which requires objective evidences, and from postmodernity, which shows that their "eternal truths" partly are formed by the culture, where they are created. The survey the quadrants offer, however, makes it possible to recognize and to incorporate what is best of premodern, modern and postmodern contributions. Without metaphysics, however, for Wilber now replaces perceptions with what goes before, namely perspectives, and asserts that phenomena only exist within the framework of the perspective an observer is able to open up. In this way, there are also "different levels of God".
But precisely for that reason, religion can become "a conveyor belt" from primitive levels to the most developed ones. Provided, though, that both science and religion cease with their confinement to the mythical level, to war-gods or the nice uncle on the cloud etc. Because spirituality, religion, God are found on all levels. Forgetful of his earlier fights against modernity, Wilber now sides with this movement, but so he is threatened with total relativism. He does not seem to realize that, just as the text is corrective in literary interpretations, so the physical world is a corrective against total relativism in the interpretation of the world.