We all do agree that today's music has been strongly influenced by the music of the past. But when we talk past, we should also talk our entire past, isn't it?
Every known civilization has had some form of music and dance. The fossil record traces of mankind's tryst with Music goes way back to the days when we were busy http://en.wikipedia.org/wiki/Evolutionary_musicology sending the mammoth to extinction. And then the ice age passed… not without impacts. We were shrunk to a population of a mere 10,000… but the planet entered a relatively stable period of the climate when man had enough settlements to work together in hunting. The brain that evolved in a period of a shrinking population, due to the sudden ability to idle up in groups only had to discover the ability to use it for attracting mates in the much the same ways birds have elegant musical songs only in regions where there is abundance. Music is a highly energy intensive mate sleection strategy that displays your ability to survive in a dense ecosystem.
Music is not just about hearing but its also about ability to reproduce sounds in specific patterns and identifying those as simple canned messages.
Where things seem to get cloudy is when we introduce humans in the picture - with their large neo-cortex. We evolved languages and since then there has been no turning back!
Music has been a widely practiced sexual selection strategy amongst several species. The basic rules still remain. We only figured out its mechanics and built elaborate rules some of which can be written down and passed on to others as memes and some of which spontaneously appear to people. A mother's lullaby almost always soothens the baby much like how everybody naturally feels a rush of dopamine when we hear a baby laugh or the good sounds evoked in a lush forest where we began multiplying again as hunter gatherers… The sound of water and how the reward of it must have been! The natural fear evoked by the sound of wolves - all get processed by a network of neurons which ultimately evoke hard-to-scientifically-explain emotions. The network is built with certain hard-wired rules.
Those rules have been exploited since a very long time to control people's heads - some of those exploits are hard-wired (such as the natural phenomenon explained above). Some of them, however, worked charmingly well for whichever purpose that 'genre' had to spread. Interestingly, all music ultimately must 'touch' the soul and that's where the science of music gets harder to explain. It must be experienced.
I'm willing to bet that every civilization must have cracked those very rules and must have had music as an integral part of their lives.
There is record of musical instruments made out of mammoth's tusks to vulture bones to the slightly more elegant stone age tools (see wp_evolutionary_musicology).
Music is a coincidentally useful artefact of how our brain perceives sounds. That very rule seem to have been cracked a long time ago and called in very many ways - some superficial abstract rules. The scientific explanation of that was however given by wp_pythagoras whose theory I've bought completely because finally it all makes sense - our dependence on the sun and the stars has resulted in us recognizing sounds associated with those times of the day to set us into the 'right' emotional states of operation. In the west, composers make music to 'describe' seasons. In the east, musical rules explain how to evoke moods.
With this perspective, to me, everything is the same. There is a music that we all feel good about - and that is the one the brain is built to feel rewarded with. Those are the little pleasures of life whose associated sounds already give us the needed happiness and 'spirit'. Much like how we figured out very complex rules for tickling our taste-buds, the various musical forms of the world are merely various ways to tickle one's 'musical taste buds'. Carnatic music had a purpose as does any lullaby.
I whistle out the 3-nodes of the C major chord everytime my baby cries and it works like a charm in consoling her. Sometimes I also sing a 'natural' song not built out of any rules. And that does magic.
Most of recorded history of music is a result of humanity's ability to settle down and find lots of idle time since the sun and our new-found ability to grow food ourselves allowed us to settle down in communities - tribes, villages and even towns. The complexity of all known historical musical systems is directly tied to the ability of those people to grow food effectively. Everything else is only finer details.
The rennaissance and its resulting new found confidence transformed music drastically too and dominated the world. But then, so was Carnatic music which “peaked” during the time when the Elephants ploughed the fields in Chola's kingdom.
The ability of the west to find labour/resources for all their energy needs was the key to the spread of western ideologies around the world. Indifferently, Western Musical systems have also enjoyed refinement and evolution during this phase. Jazz is nothing but the music by the once oppressed african slaves. That system is built very much on the same set of rules they were exposed to while they were _really_ toiling the soils. The churches shone hope through their gospels while the elites enjoyed more refined forms carried over pristinely over generations since the success of the Renaissance period.
Today we are at the height of the joblessness, powered by yet another powerful source of energy besides the Sun for growing food - Oil. //www.overthinkingit.com/2008/09/23/the-hubbert-peak-theory-of-rock-or-why-were-all-out-of-good-songs/ to show that Rock peaked around the time the US peaked oil production!
Music is an artefact. But a great one at that. Its an experience which brings with it its rewards. It can heal, it can energize - it can dumb you down too, if need be. There are tricks and there are tricks. Mankind has knowingly or unknowingly exploited many of these rules.
Down the hubbert's slope, we shall know how music evolves further!