A Text book of Psychology

of numerous observations, or prescribes experiments in which you are to observe for yourself ; and you find that these results or experiments are grouped under certain main headings (mechanics, heat, electricity) and are made to illustrate certain comprehensive laws (Newton's laws of motion, Kirchhoff's law of radiation, Ohm's law of the strength of the electric current). All scientific text-books, whether the science is physics or chemistry, biology or psychology, philology or economics, are of the same pattern. It is worth while, before we begin our special study of psychology, briefly to consider some of the questions which this definition of science suggests. How, we may ask, do the various sciences come into being ? How are they differentiated, their several fields laid out and marked off? What do we mean when we say that the facts of any given science are related to one another? What is the nature of the relation ? What precisely is a scientificlaw ? Why is it important for the progress of science that laws should be established ? An answer, even a rough answer, to these questions will help us to understand the scope and aim of psychology. First of all, then, it is plain that all the sciences have the same sort of subject-matter; they all deal with some phase or aspect of the world of human experience. If we take a mere fragment of this world, ? say, our own experience, during a single day,?we find it a rather hope- O..ua less mixture. Our lawn-sprink...