As one who has experienced all sorts of memory over 70 years I'll say that Ed's analysis is technically correct (although I'd disagree with the muscle memory being the most dangerous, it has saved my butt a number of times on the ski slope - but an aerial recovery from an unseen bump isn't the same as playing a fixed piece of music - so regarding music he is accurate).
But, as I'm still a newbie, I wonder about the nature of the pieces (and this is a question, not a statement). I've not yet branched out into Baroque lute - and I gather from the messages on the list that they are more of a "set piece" style with several instruments playing. But regarding the renaissance lute it was on this list that I learned that "divisions" are actually almost a form of ornamentation - at least that is the way I'm looking at them for the moment. The pieces in my limited collection (from McFarlane's Scots Lute, Damiano's Method, and the kindness of many of you who have posted pieces on the web which now fill a notebook of printouts) all seem to have the characteristic of divisions as variations. A repeated theme, sometimes quite short, with variations. Perhaps my analysis of that era is wrong, but if right it would seem that the memorization need only be the theme and that the variations could vary, and yet fit with the continuo or the other instruments. It raises the question as to whether the written music of those days really reflects the play, or merely the composer's guides to his piece that he might have varied himself. Unlike the full orchestral scores of a bit later the instruments might have been played more freely. This is speculation, and I bow to the more knowlegeable. But I wonder if the aural memory, combined with a good feeling for the scales and harmonys, might be the best memorization for the lute. The sense of the song may be just the way the old boys played. Best, Jon To get on or off this list see list information at http://www.cs.dartmouth.edu/~wbc/lute-admin/index.html