MOST OF MY adult life I have asked, "How can I know this is true?" concerning whom or what I put my trust in. It's a broad, maybe naive, question, applicable to any discipline from science to history, up through hard-to-fathom philosophical doubts and down to our need for assurance in our friendships and ethics. Ken Wilber's integral philosophy spans every conceivable discipline but the way he applies his own unique "testing" method to spirituality is particularly important to me.