A core concept in Wilber's philosophy is the concept of the holon, which he borrowed from Arthur Koestler. The idea is that everything is not only a whole, but also part of a larger whole, so a "part/whole" or "hol-on". That is true for atoms, molecules, organisms, human beings, but also for letters in a word, words in a sentence, sentences on a page, pages in a book, etc. -- as the familiar holistic sequence goes.