Introduction

Abstract

Many people plan their summer vacations in March or April and would like to know in advance what weather conditions are going to be. Unfortunately, no reliable weather forecasts can be made three or four months in advance at least in the present state of the meteorological science Similarly all investors around the world would like to know the date of the next property or stock market crash, all sugar producers would like to know whether and when there will be a downturn for the price of sugar. These are undoubtedly “practical” questions, but they are not yet “solvable”. In this introductory chapter we explain why it can be of good strategy to put aside the question of practical usefulness (at least for a while) and to concentrate on those questions one is able to solve, however insignificant they may seem at first.