Quote from whitster:
"Mandelbrot studied the clumping of 3 sigma and greater events and their implications in natural systems. He then found the same phenom in the markets. Lastly he was unable to ascertain direction but could forecast volatility."
which is part of the reason why people can use TA effectively.
TA is not about saying "i know what the market will do"
it's about being able to enter longs and shorts that offer compelling risk/reward and that ability comes, in large part, from understanding the cyclical nature of volatility.