This is just another question that has been on my mind for the past few hours, so I thought I'd share it! It's conveniently facilitated by the other recent thread about a composer outdoing himself, but this question has a slightly different perspective.
The question is, quite simply, whether or not you believe that the notion of a 'magnum opus' is a useful one. First, to clarify, a 'magnum opus' is the work of a given composer (or any artist) perceived to be their greatest. Brahms's Ein Deutsches Requiem or his Fourth Symphony are often cited as his magnum opus, but is there any sense in making such distinctions?
I ask because this idea seems to imply that the composer's greatest achievements are all contained within one piece; there is distilled in this given piece every aspect of the composer's perfected style. In a sense, it epitomises who they are.
It seems to me, however, that it's more valuable to consider a composer's full oeuvre as a chronological spectrum - a personal and characteristic style that develops over time; the initial, immature pieces being just as characteristic as the (usually late) masterpieces. In terms of form, structure and instrumentation etc., the magnum opus could perhaps be demonstrated as a work of perfected craftsmanship, but I don't think any single work can ever embody every aspect of an individual's artistic philosophy. That is something better viewed as a secondary manifestation of a composer's complete works.
This seems especially true of more modern composers who often quite easily fluctuate between wildly different styles, making the distinction of a magnum opus utterly pointless, because one piece could never represent more than the one style in which it is composed.
But what do you think more generally?