In the Symposium, Socrates argues that in order to desire something, we must lack it. We can’t desire what we already have. Better yet, we can’t desire what we already think we have:
Anyone, who has a desire, desires what is not at hand and not present, what he does not have, and what he is not, and that of which he is in need; for such are the objects of desire and love. (Plato Symposium, in Reeve 2012: 184)
But it goes further than that. We cannot desire what we aren’t aware we lack. So, if personal computing doesn’t exist, we can't say that’s what we want. Unless we have the imagination of Steve Jobs, who famously said; ‘people don’t know what they want until you show it to them.'
Most of us? We need to be shown.
The nature of desire goes the other way, too. If we aren’t aware that we are already rich, how easy is it to desire more money? That’s not to say desiring money is bad - it’s not about the money. It’s about the dreams and wishes we can indulge with that money. We want the things that money represents:
Money takes wishes, however vague or trivial or atrocious, and broadcasts them to the world, like the Mayday of a ship in difficulties. Unlike the Mayday, it appeals not to sensations of individual benevolence or common humanity...but offers a reward that is not in any sense fixed or finite - there is no objective or invariable value in money - but that every person is free to imagine in the realm of his own desires. (in Frozen Desire, James Buchan, 1997, p.19).
This process of imagining a future, desiring that future, going after it via money - is the engine of progress. It works because money moves from person to person, mobilising wish upon wish, setting the future in motion. That’s why it matters where and how and why we spend our money: money is a symbol of our desires, and our desires shape our world.