II. The Nature of Knowledge.
What is the nature of knowledge? In asking this question we use the word "knowledge" in that particular sense in which it signifies the object and aim of all scientific endeavours. (What is it, really, that we are seeking in disinterested scientific research?)
Scientific thinking is not essentially different from thinking in every day life, it is only a higher stage of it. Scientific knowledge is a continuation of practical knowledge, such as human beings need in order to exist and to live well. They cannot live without knowledge and thinking, because they lack the sure guidance of instincts by which animals are led comparatively safely through life's troubles. Nature has instead endowed man with reason, and reason is a much better tool and guide than instinct, because it is infinitely more adaptable and flexible. An instinct is rigid, it is adjusted only to a particular kind of situation whereas reason does the adjusting itself and is therefore able to prescribe the proper (i. e. most useful) actions for any situation. (The possibility of this is seen immediately when the nature of knowledge is analysed.)
What is required to get the best possible adaptation of a living being to its surroundings? (Obviously it is necessary to have all its activities adjusted to continually changing circumstances.) Each situation will be a little different from all previous situations, and sometimes it will happen that the organism is confronted with entirely new circumstances which seem to have no resemblance with former experiences. (A perfectly well adapted organism must be prepared for everything, but instinct can prepare it only for a limited number of typical cases because it is formed by circumstances that recur continually for many generations.)
How does human reason manage to prepare man for the unforeseen? How can it foresee what has to be done in a case with which it has never been acquainted before? Certainly not by means of some miraculous power
