My point was that there is no one out there who exactly knows what the future will bring us, so in that sense everybody, is a "noise trader", meaning that their decisions are guided by "hueristics and biases".
Put differently, there are no "rational" traders, whatever rational means.
If the "vast majority" of the traders behave irrationally and deny the uncertainty through conventional forecasting practices that make their actions predictable by the small number of traders able to behave rationally (i.e able to understand and predict the irrationality), then for the latter rational trading will be possible as "speculation" in Keynes's sense of "forecasting the psychology of the market" and "aping unreason proleptically."
An example, according to Keynes, is that:
"very few American investors buy any stock for the sake of something which is going to happen more than six months hence, even though its probability is exceedingly high; and it is out of taking advantage of this psychological peculiarity of theirs that most money is made." (Collected Writings, vol. XII, p. 78)
Ted
