The historian Niall Ferguson once edited a book called Virtual History. The purpose of the book was to explore the power of the counterfactual; through the course of nine chapters its various contributors, each experts in their respective historical fields, considered what the consequences would have been of alternative outcomes to such events as the Battle of Britain, the American Revolution and the Cold War. A similar exercise could surely be undertaken in relation to the history of music, and specifically in relation to the most agonising counterfactual of all, namely what would have happened if composers who died having yet to write their best music had lived to write it.
We have recently started playing the first string quartets of Schubert and Mendelssohn, and these provide occasion for considering the great lost works of the past. Schubert and Mendelssohn (along with Mozart, whose early quartets have been considered here previously) have much in common; in particular they were renowned child prodigies (Schubert wrote his first quartet at the age of thirteen, while Mendelssohn wrote his Octet and Midsummer Night’s Dream Overture, both still standards of the concert repertoire, as a teenager) and they died in their thirties. Of course the question of what more was to come from a composer does not just apply to those such as Schubert and Mendelssohn, whose flame burned so brightly so young but which was extinguished so early. Few composers ever knowingly write their final works; we think of Beethoven’s Ninth as the apotheosis of his life’s work, but we know also that he was working on his Tenth when he died (and if the last quartet is any clue it would almost certainly have been far less grand in its vision than the Ninth, representing a whole new kind of symphony). Mahler’s Tenth and Elgar’s Third were originally unfinished but later became the complete works we know them as today, through the gallant efforts of those who assembled and developed the fragmentary plans for the incomplete parts (a process which is also reported to be in progress for Sibelius’ notorious Eighth, at which the composer toiled for a decade before abandoning it). And of course Schubert himself wrote the most famous of all unfinished symphonies, his Eighth, although he did manage to finish his Great Ninth before he died.
It is doubtless maddening to discover half-finished or barely-begun compositions by the old masters, leaving their successors to try and work out what would have happened next. But in a sense we are lucky to have such fragments. What of all the things unwritten, all the embryonic ideas conceived but not yet committed to paper and lost forever, or even those ideas not yet conceived but which would surely in time have emerged from the magnificent minds of men cut off in their prime? Virtual music may make a diverting parlour game, but in the hands of the eternally youthful trinity of Schubert, Mendelssohn and Mozart it assumes a real sense of tragedy.