Happiness is determined by factors like your health, your family relationships and friendships, and above all by feeling that you are in control of how you spend your time.

When action is needed, optimism, even of the mildly delusional variety, may be a good thing.

Many people will admit that they made a mistake [putting money in dot-coms or telecoms at their peak] But that doesn’t mean that they’ve changed their mind about anything in particular. It doesn’t mean that they are now able to avoid that mistake.

Unfortunately, skill in evaluating the business prospects of a firm is not sufficient for successful stock trading, where the key question is whether the information about the firm is already incorporated in the price of the stock. Traders apparently lackthe skill to answer this crucial question, but they appear to be ignorant of their ignorance.

Finally, the illusions of validity and skill are supported by a powerful professional culture. We know that people can maintain an unshakeable faith in any proposition, however absurd, when they are sustained by a community of like-minded believers. Given the professional culture of the financial community, it is not surprising that large numbers of individuals in that world believe themselves to be among the chosen few who can do what they believe others cannot.

There are domains in which expertise is not possible. Stock picking is a good example. And in long-term political strategic forecasting, it's been shown that experts are just not better than a dice-throwing monkey.

People talk of the new economy and of reinventing themselves in the workplace, and in that sense most of us are less secure.