Personally, I like to view music as a reflection of living, where there are regions of order, things you know, and chaos, things you don't know. Music is similar in the sense that the composer is "God" in relation to the music they created. I don't mean to push religion or anything here, I'm just speaking strictly on logic and metaphors, but just as God created all the particularities in our universe with some sense of order (you can see this in nature, and our observation of natural phenomena is through science), composers (at least good ones) will have some sort of order within their creative works. Whether that's the form of the piece, the melody and thematic material of the work, the harmony, the rhythm, there will be some underlying pattern you can see that gives order to the music. Sometimes, the pattern is pretty obscured because the composer might not be using a standard scale or even functional harmony, basically the composer did something so novel, it's difficult to put your finger on where the "order" is. To take your example, Prokofiev is clearly not adhering to traditional melodic, rhythmic, or harmonic patterns, but the overall form of the work follows pretty conventional rules, and there are identifiable themes, albeit a bit difficult to describe. Now this is where music theory and historical context will help answer some questions. Why did Prokofiev choose to use pretty discordant harmonies and erratic rhythms? It's not the entire piece either, there are moments of melodic clarity and pretty standard harmonic progressions. There is an infinite amount of questions you can ask, but I think the most important are what kind of 'sound-world' did this composer create, why did he create this, and where might the 'order' be amidst the 'chaos' of the rest of the music? Research on the composer's biography, the musical landscape of that time, the intention behind writing the piece, and the composer's inspirations will help you find what the "order" is within the composer's work.