Originally posted by joe shmo
It is often said that history repeats itself,....
Its the sort of statement that is guaranteed to come true. It is always possible, for almost any event in history, to find some prior event with something in common and then say 'well history repeated itself'. In many cases, there will be many things in common.
..could it be that the state of human society can be represented as a periodic signal, and if it could, how might the waveform behave.
Although it is trivial to find events that have happened before, it would be much harder to find a periodic pattern. This is only likely to be the case in systems where such periodicity arises from the system - eg the stock market.
But I think you would find a lot of different systems interact to make up human society, and humans are not really one single society, so you have different societies interacting. So rather than a single wave form, you will have a highly complicated wave almost indistinguishable from white noise.
The population is growing, wealth is increasing, knowledge is increasing, family sizes are falling, culture is changing to a more peaceful society, etc. So there are significant long term trends.
If we could start to map this waveform, we could then decompose it into its harmonics ( Fourier analysis )
Much easier to start in the other direction and identify the inputs and see how they create the wave.