At the top of the list of economic theories based on clearly false assumptions is that of Rational Expectations, in which humans are assumed to be machines programmed with rational responses. Although we all know – even economists – that this assumption does not fit the real world, it does allow for relatively simple conclusions, whereas the assumption of complicated, inconsistent, and emotional humanity does not. The folly of Rational Expectations resulted in five, six, or seven decades of economic mainstream work being largely thrown away. It did leave us, though, with perhaps the most laughable of all assumption-based theories, the Efficient Market Hypothesis (EMH).—-Jeremy Grantham, GMO
On the other hand, technical analysis assumes that investors are emotional and selectively irrational. I know what makes more sense to me.
HT to The Big Picture