So you'll be an Austrian nobleman, commissioning a symphony in C

One of the reasons I like having easy access to central London is that in a city this size, you'll always find a whole bunch of shops that would have real difficulty surviving elsewhere. What's more, the modular way London has developed (it's really just a collection of villages and small towns smooshed together into one gigantic whole) means that you're very likely to find entire streets that are heavily weighted towards one type of shop.

For example, Rupert Street and Berwick Street in Soho (they're end to end, so are effectively the same road) are packed to the gills with little record shops. I've spent a happy few hours in Cheapo Cheapo Records, poking through shelves full of CDs where I recognised maybe one in ten of the bands, and choosing music based entirely on whether I liked the name of the album. (Current front-runner: Hellogoodbye's Zombies! Aliens! Vampires! Dinosaurs!)

Go into any of these shops and you'll find a mind-numbing array of musical genres. Find a specialist shop for one of these, and it gets even more complicated; Wikipedia lists thirty different varieties of metal, twenty-eight of punk, twenty of country, the list goes on. Mix in all the types of music that isn't sold in these shops at all (the various flavours of classical, music-hall, opera etc.) and it just gets ridiculous.

However, I reckon that these splits boil down, in the end, to just one major difference, and it's not necessarily one that you'd expect. Rather than splitting the genres based on the types of instrument that are played, or by the age of the music, I think the best way to look at it is the underlying philosophy of the song's composer, and what they thought of the relationship between musician and audience.

Let's go back as early as we can to look into this more. In the Bible's Old Testament (which is pretty darned early), music is found in two places — people's homes and workplaces, and in worship. Even then, worship music is an extension of that found in the home — people wanted to express their love for God in many ways, so they took the things that meant the most towards them and deeply moved them, and turned them towards praising Him. In that way, music comes up from the people as a whole. Even when there are specific Temple musicians leading the people, everyone's joining in, in a many-to-many interaction. Let's call this the bottom-up model of music.

Even in the Old Testament, though, we see parts of the other model. In 1 Samuel 16, King Saul is being tormented by an evil spirit (from the Lord, apparently – there's an entire theological debate to be had in that verse alone, but it's one that we are emphatically not having here), and he gets David to come and play the harp for him, to soothe his mind. Here we have a one-to-one interaction: Saul isn't taking any part in the music, he's just listening to David. David is, essentially, the first court musician, someone employed by the rich and powerful to play music for a select group who do not themselves participate. This is the top-down model.

OK, getting both of those out of the first few books of the bible is maybe a bit of a stretch, but both models have definitely been in place throughout history. By the time we reach mediaeval times, there's a definite split. People in their communities create their own music for participation, and the composers and musicians are a part of the community. In the houses of the rich and powerful, however, musicians tend to be employed. As such, they are explicitly not part of the community. What's more, because the music they play is also bought (or commissioned), it tends to be created by a single person, then propagated out by the musicians to a non-participatory audience — one-to-many. Once again, it's coming from the top down.

Fast forward to the present day, and we can still divide musical genres into these two models. In a classical concert, the music has been created by a single person. It's played by a large (and therefore anonymous) group of musicians, who are controlled by a single, powerful figure (the conductor) and have little opportunity to put something of themselves into the performance besides competence. And the audience is generally not going to do much more than sit there. I'm not saying that it's going to be bad music — the audience may well be enjoying it tremendously – but they are definitely in a passive position of receiving the music rather than joining in.

In a rock gig, on the other hand, the composer is often one of the musicians, all of the musicians will have defined, unique and visible roles, they'll be facing the audience rather than a conductor, and the audience itself will be jumping around a lot more. One more thing — rock musicians very rarely play from music at a gig, whereas classical musicians generally do. The implied message is that the rockers are actively encouraged to improvise bits, to put their own spin on the song, and to just rock out, dude. This often results in a much messier performance, but that's the whole idea.

If you start looking at music with these models in mind, you end up splitting the genres in unexpected ways. For example, folk music may look and sound completely different to speed metal, but both are bottom-up. And a comedy-oriented post-punk band like They Might Be Giants might share certain similarities with Tom Lehrer's comic songs, but Lehrer is firmly in the music-hall tradition, which is top-down.

Although the two models are very different, there's not usually any conflict between them because they tend to be found in very different venues. However, there's one place where the two clash on a regular basis, and it's one that brings us full circle: the church. The heated (not to say vitriolic) disputes between those who want traditional organ music to accompany church services, and those who want contemporary guitar-based tunes, has very little to do with the choice of instrument and everything to do with the model of worship that people want.

A church organ is pretty much the only instrument that can't cross the divide between top-down and bottom-up. "Classical" instruments do it all the time (the trumpet is just as comfortable in a marching band as it is in a jazz quartet), but playing an organ is necessarily an isolating activity, and hence they don't work well with other instruments, making them necessarily top-down. And that makes them the perfect choice for those who see worship as something that is led from the front, handed down from on high. Making up a band from the congregation, on the other hand, where people bring along their own instruments and lead from the floor, is the natural extension of the idea that worship comes up from the people and is expressed in their way.

I'm not going to suggest that either model is in any way better (although you can probably guess which way my preferences go, given that I was reading the Guardian at lunchtime today and I'm currently listening to The Who). But it is an interesting way of looking at something that's not only been of immense importance to humanity ever since humanity was first...well, human, but is also an integral part of the world around us. Music's a powerful thing, a shortcut to our memories and emotions — it's worth thinking about to see how much of our society is tied up in it.