How much of Shakespeare is really Shakespeare?

[Elvira Cardigan]

The canon as we now have it is a relatively modern creation. Many plays previously ascribed to 'Shakespeare' are now rejected. Other have been assimilated that were previously ascribed to other authors. Doesn't this raise the possibility that he entire image of 'Shakespeare' as a cohesive single entity (whatever his real identity) is illusory?

Could there never have been a single 'Shakespeare' in quite the way we imagine? Could he (whoever he was) have written only some of the plays that bear his name? or parts of them?