The economist John Maynard Keynes argued that market behavior could not be rational, or subject to improvement, since our existing knowledge did not provide a sufficient basis for a calculated mathematical expectation of investment returns. I think this observation is particularly true when the object of speculation involves the application of a new technology, such as the Internet.

Modern financial theory attempts to surmount the problem of an unknowable future by suggesting that returns can be predicted by measuring the past volatility of share prices -- shares that exhibit higher volatility are expected to yield greater returns. Yet this assumes the future will be a continuation of the past -- like steering a car by looking in the rear-view mirror. Investors therefore remain heavily dependent on their emotions. The feelings of "greed" and "fear” , that drive markets remain constant throughout the ages.

經濟學家約翰·梅納德·凱恩斯曾經說過，市場的行為不可能是理性的，也不可能改進，因為我們現有的知識不能為經過精確計算而得出的投資收益預期提供充分的依據。我認為在投機對象涉及到新技術的使用時，例如因特網的使用，凱恩斯的這種看法尤為正確。

現代金融理論試圖解決未來不可預測的問題。按照現代金融理論，投資收益可以通過對股價以往的波動幅度來預測，也就是說，股價波動較大的股票可望帶來較大的回報。但是這種理論是以未來是過去的延續為前提的，如同看著后視鏡駕駛汽車一樣。所以投資者仍然在 很大程度上憑著自己的情感操作。在任何年代，推動市場的“貪心”和“擔心”這兩種心情 總是永恒不變的。