>>21650I'd not focus on whether internal or external contradictions are more important in general (part of dialectical materialism is the rejection of universal logic - no need to generalize things this abstract), instead it's important to just know that both internal and external contradictions exist, and both may spur development. For dynamic systems that are self-moving, internal may play a larger role. For a rock - what internal contradictions are impelling it to change? Another important piece is also Mao's idea that external contradictions only work via internal contradictions. (I think this can probably be justified scientifically, but some people are very against finding dialectical principles like this in nature. It's important imo to not just apply abstract philosophical logic in a blanket way unless its proven to apply to a reasonable large number of domains. Else we just turn Mao into Sun-Tzu). As far as primary and secondary contradictions, I think of it practically (I don't think it holds any real strength as a concept otherwise; i think these things are able to be shown empirically but not beforehand, at least in social issues), like sudoku. In sudoku there are lots of 'contradictions', but usually you'll be pulling at one thread and that lets you pull at another, and so on, until the whole puzzle is solved. I think this relates best to practice, though, and not theory.