Just like to hear people's opinion on this. Is it possible to prove either side of the debate?
Well - the way i see it there are 2 schools of thought on technical analysis.
Predictive (triangles,elliots,fiobanacci etc,) and reactive (trend following).
With both you can hav a certain element of self fulfilling prophecy given that you can have a large amount of people looking at some technical signal and all acting the same way once it occurs.
SO putting that aspect of it aside, I haven't done any real proper research on the predictive side.
But if you're asking for my gut instinct then i think no. (strongly suspect that in fact)
As for trend following, I think that basically it gives you a value bet.
A bit like getting 5/4 on teh flip of a coin off a bookie.
Identify enough value bets and use proper money management then you can develop a system that produces a positive expectancy.
Of course - whatever system you use it is absolutely doomed for failure if you do not employ proper money management.