The following traditional Chinese philosophical ideas embody the concept of contradiction

This question is somewhat comprehensive. Options A and B reflect the role of the identity and struggle of contradictions and the idea of the transformation of contradictions. Option C illustrates the universality of contradictions. In option D, "harmony but difference" is differentiated sameness, and "sameness but discord" is undifferentiated absolute sameness, which means that the sameness and struggle of contradictions are dialectical ways of solving contradictions. Therefore, the correct answer to this question is ABCD.