The wiki entry on I Ching says it is important for both its philosophy as well as being an oracle. Here is the section on philosophy:
This section seems to indicate as a philiosophy it is most relevent to metaphysics, ethics and cosmogony, does everyone agree those are its most important philosophical contributions ?
Philosophy
Yin and yang, while common expressions associated with many schools of classical Chinese culture, are especially associated with the Taoists.
Another view holds that the I Ching is primarily a Confucianist ethical or philosophical document. This view is based upon the following:
Both views may be seen to show that the I Ching was at the heart of Chinese thought, serving as a common ground for the Confucian and Taoist schools. Partly forgotten due to the rise of Chinese Buddhism during the Tang dynasty, the I Ching returned to the attention of scholars during the Song dynasty. This was concomitant with the reassessment of Confucianism by Confucians in the light of Taoist and Buddhist metaphysics, and is known in the West as Neo-Confucianism. The book, unquestionably an ancient Chinese scripture, helped Song Confucian thinkers to synthesize Buddhist and Taoist cosmologies with Confucian and Mencian ethics. The end product was a new cosmogony that could be linked to the so-called "lost Tao" of Confucius and Mencius.
- The Wings or Appendices are attributed to Confucius.
- The study of the I Ching was required as part of the Civil Service Exams in the period that these exams only studied Confucianist texts.
- It is one of the Five Confucian Classics.
- It does not appear in any surviving editions of the Daozang.
- The major commentaries were written by Confucianists, or Neo-Confucianists.
- Taoist scripture avoids, even mocks, all attempts at categorizing the world's myriad phenomena and forming a static philosophy.
- Taoists venerate the non-useful. The I Ching could be used for good or evil purposes.
http://en.wikipedia.org/wiki/I_Ching
This section seems to indicate as a philiosophy it is most relevent to metaphysics, ethics and cosmogony, does everyone agree those are its most important philosophical contributions ?