A Westerner's question about traditional Chinese medicine: are the Yinyang concept and the Wuxing concept of equal philosophical and medical rank?

There is no question that the theoretical and practical value of the Yinyang concept is by far higher than the value of the Wuxing concept. I consider Yin and Yang as one of the greatest discoveries ever made, being deep philosophy as well as deep science. Using this concept seems usefull even in combination with the most advanced methods of modern pathology, diagnosis and therapy. The Wuxing concept, however, I consider as a purely speculative system without logic and reason. The probability that it leads to useless or even wrong conclusion seems much higher than the possibility to result in something usefull. I know tha many TCM authors and practitioners will object. However, I see good reasons to demand one thing: that they should prove in detail, why they consider that Wuxing concept not only as helpful and useful, but even as essential for the future of TCM.