This book describes the different types of concepts and statements that compose a scientific body of knowledge. And we expect that scientific knowledge provides a typology, predictions of future events, explanations for past events, sense of understanding, and control of events. Among these purposes typologies can be achieved since any set of concepts can be used to organize and classify. For sense of understanding, it is provided only when the causal mechanisms that link changes in one or more concepts (the independent variables) with changes in other concepts (the dependent variables) have been fully described.  Also this book indicates characteristics of scientific knowledge which are abstractness, intersubjectivity, and empirical relevance. Abstractness should be independent on the time and space and intersubjectivity should include explicitness and rigorousness. For empirical relevance, other scientists can evaluate the correspondence between the theory and the results of empirical research.

In Chapter 2, author introduces Kuhn paradigms which are scientific revolutions. While examples of Kuhn paradigms are founded well in the physical and biological sciences it is not easy to find example in the social science. However Freud’s ideas were a good example to meet the criteria of Kuhn paradigm. Also author explains that a paradigm and a Kuhn paradigm differ in degree; the Kuhn paradigm represents a dramatic change from past orientations, whereas a paradigm represents a definite shift in orientations, but less than a scientific revolution.

I learned what exactly concept is, difference between abstract and concrete concepts, relationship between abstract concepts and operational definitions, and quantifications of theoretical concepts as well in the chapter 3. And I also learned that there are four kinds of forms of quantification such as nominal level, ordinal level, interval level, and ratio level.

In chapter 4, author emphasizes that theoretical statement of the form (Given C1 …. Then Y) are most important for scientific body of knowledge and it should be placed before explanation, predictions, or sense of understanding.