What's your favourite album of all time ('Grace', since you ask)? Let's assume, for the sake of argument, it was released pre-iTunes store, ie before 2003. I'll bet there were songs that didn't hit you immediately, songs that you only grew to love over time.
Now imagine you'd bought that album post-iTunes, with the option to preview and purchase individual tracks. Would you have bought every song? Honestly? Or would you have just cherry-picked the ones that sounded good on first listen?
It's an old argument, all a bit Word Magazine - but it's been yanked abruptly back into focus by (sorry, there's just no way to make this sentence interesting) Pink Floyd's decision to sue their record label EMI in a dispute over online royalty payments.
Their beef? Pink Floyd don't want their albums parceled up into individual track downloads. Now, you might say it's a little unfair of the band to target EMI - as if they don't have enough problems already, what with being dollars of dollars in debt - rather than iTunes.
After all, it's the retailer, not poor EMI, who insist, using their monumental industry clout, that single tracks must be made available. No arguments. If you don't play ball, your music won't be stocked.
Faced with the implacable market-leading might of iTunes, even Radiohead relented in 2008, having previously been fiercely opposed to having their albums broken up.
All of which quarries some pretty fundamental questions about what music is. Are albums sacred entities that need to be upheld in their original format? Which is the critical form - the album, or the track? And who gets to adjudicate?
Call me a tweedy, reactionary twat, but I'm with Pink Floyd on this one. Sure, it might seem high-handed of the band to deny the wishes of consumers. If someone wants just one song, they shouldn't be forced to buy the entire album.
On the other hand, music isn't like cornflakes, or home insurance. This is art we're talking about, not commerce - 'consumer rights' only go so far. Why should one digital retailer define the limits of what constitutes the 'work'? Isn't that for the artist to decide?
Pink Floyd's attorney Robert Howe describes the band's albums as "seamless pieces." No-one who's heard 'The Dark Side Of The Moon' would quibble with that. The band are not being unreasonable here, or disdainfully old-school; they're defending their art in the face of cold, hard, multinational business reality.
And their logic is sound. If you extended the iTunes model to other art forms, and allowed people to purchase only the bits they fancied, you'd have to sell The Wire DVDs containing just the Stringer Bell scenes, or boxsets of Mad Men featuring only episodes in which something actually happens (it wouldn't leave you with much).
This is a stand worth taking. The iTunes era threatens to dismantle the whole concept of the "classic album" - the great work (and yes I know I'm bandying that work round like I'm Brian bloody Sewell or something) as an irreducible entity that needs to be appreciated as a monolithic whole.
Post-X Factor and Glee, there's a danger we're hurtling towards a world where people buy the tracks they've heard on TV, and ignore the rest.
'OK Computer'? Sure, I could probably live without 'Climbing Up The Walls' and 'Electioneering'. And I guess, even on 'Grace', the absence of 'So Real' wouldn't break my heart.
But my life is richer for having lived with those lesser-loved songs for 15 years. Sometimes, it's not all about what we want as consumers. It's about what we ought to accept, as adults and serious music fans.