Recent science textbooks are designed for persuasion and education. Works intended for these purposes often do not align well with actual scientific activities. This book fundamentally aims to reveal that we have been misled by such materials. Unlike the conventional approach in the scientific community, this book draws a new concept of science from the historical record of research activities themselves. However, if one seeks data and investigates history solely to answer the stereotypical knowledge from textbooks, no new concepts will emerge from such historical examinations. The result has significant implications for the essence and development of science. If science is merely an accumulation of facts, theories, and methods in contemporary textbooks, then scientists are merely adding a few elements to this collection, and the development of science becomes a heap of techniques and knowledge. Consequently, the history of science becomes a chronology of continuous accumulation and the obstacles such as myths and superstitions that hindered this process. In such a scenario, historians of science perform two roles: identifying the origins of scientific facts and explaining them concerning the development of science. However, recent historians of science assert that the concept of cumulative progress is becoming increasingly difficult to sustain. In this process, various aspects of science are highlighted. One such aspect is that the methodologies for deriving conclusions for different types of scientific questions are often insufficient. Previous views were partially derived from the imperatives of scientific observation and methods, where observation and experience must drastically limit the range of acceptable scientific beliefs; without this, science would not exist. Another aspect is the arbitrary elements introduced among scientists for personal or historical reasons. However, the involvement of arbitrary elements does not mean that scientific activities can proceed without accepted beliefs. At least for mature phases, the answers to these questions are inherent in the educational transmission among scientists. When these traditions and anomalies cannot be avoided, the abnormal episodes causing shifts in disciplinary commitments are termed 'scientific revolutions' in this book. Scientific revolutions are tradition-breaking activities that complement tradition-bound normal science activities. The expanded concept of the nature of scientific revolutions will be explained in subsequent chapters. Additionally, we will explore how conventional concepts like verification or falsification in the theory of scientific inquiry will be replaced. This approach aims to subject other fields’ theories to the same rigorous examination, not merely logical or methodological distinctions preceding knowledge analysis.

In this book, normal science refers to research activities firmly based on one or more past scientific achievements. These achievements provide the foundation for further practice and are acknowledged by a particular scientific community for a period. Recently, these achievements are detailed in introductory and advanced science textbooks. These works explain the core of accepted theory for scientists, elucidate successful applications or a significant portion thereof, and compare these applications with exemplary observations and experiments. Such texts implicitly define the relevant problems and methods for the next generation of researchers in the field. They can do so because they share two essential characteristics: they are remarkable enough to attract an enduring group of adherents away from competing views and flexible enough to leave all kinds of problems for the redefined group of practitioners to resolve. Achievements possessing these two characteristics will henceforth be referred to as 'paradigms.' This is closely related to 'normal science.' The term paradigm suggests models of scientific activity that form specific coherent traditions of scientific research, encompassing laws, theories, applications, and instrumentation. Studying a paradigm prepares the scientist to avoid overt disputes about basic concepts during their ongoing activities, ensuring commitment to the same rules and standards and preparing them to become members of the specific scientific community that will carry out future scientific activities. Such commitment and the resulting clear consensus are essential for the emergence and continuation of normal science, i.e., a particular research tradition. There is a discussion about whether the shared paradigm can be entirely reduced to logical fundamental elements that might act as a substitute for someone studying the development of science, and these questions and answers will be the foundation for understanding the concepts of normal science and related paradigms. Those who do not wish to or cannot adapt their research to a new paradigm must either continue their work in isolation or move to another group. Defining a scientific group more thoroughly leads to different outcomes. Once an individual scientist accepts a paradigm, they do not have to struggle to re-establish their field from first principles in their primary research. This can be left to the textbook authors. Given a textbook, a creative scientist can conduct research from where the book ends. They have acquired the paradigm that can guide the research of the entire group.

What is the nature of the more specialized and profound research permitted by the acceptance of a single paradigm by a group? Such questions become more urgent if we note one aspect of the terms used thus far that might mislead us. In established usage, a paradigm becomes a recognized model or pattern, and in the absence of a better term, the word paradigm has been co-opted for its semantic aspect. However, in conventional science, paradigms are rarely objects of imitation. Instead, like accepted legal precedents, paradigms must be further clarified and characterized under new or stricter conditions. To see if this is possible, we must first recognize how limited both the scope and accuracy of a paradigm are when it first appears. In fact, someone who has never engaged in mature science cannot appreciate how much work remains after a paradigm emerges, nor how attractive completing this work can be. Therefore, most scientists devote their lives to completing these tasks, which constitutes normal science. The aim of normal science is not to uncover new kinds of phenomena. In fact, phenomena that do not fit within the paradigm are often not seen at all. Scientists are not aiming to invent new theories or readily accept theories devised by others. Instead, normal science research aims to articulate the theories already supplied by the paradigm. Normal factual scientific inquiries focus on three main types: first, determining significant facts revealed by the paradigm; second, the workaday determination of facts that can be compared with the predictions derived from paradigm theory; and finally, empirical research conducted to articulate the paradigm theory. These tasks resolve some of the theoretical ambiguities and allow solutions to problems that were previously only interesting. The theoretical research within normal science, though a smaller part, involves using existing theory to predict factually valuable information. The need for such research arises from the frequent obstacles encountered while developing the contact points between theory and nature. These three types of problems—determination of significant facts, comparison of facts with theory, and theoretical articulation—comprise the entirety of normal science literature, both in experimental and theoretical sciences. However, this literature is not solely composed of such issues. It also includes non-standard, exceptional problems, whose resolution gives scientific activity its special value. Before considering such revolutions, it is necessary to provide a comprehensive overview of the body of normal scientific research that paves the way to them.

One of the most striking characteristics of the problems of normal research we have just examined is that such research rarely aims to produce major conceptual or phenomenal new discoveries. Even when the research aims to clarify the paradigm, it does not aim at unexpected novelties. But if the goal of normal science is not substantial innovation, why are these problems addressed in the first place? The reason is that it increases the scope and precision of the paradigm's applicability. However, this answer does not explain the enthusiasm and dedication scientists show towards problems in normal research. While calculating astronomical tables or obtaining data from many measurements with existing instruments is meaningful, scientists often see this as a mere repetition of previous processes and think little of it. This resistance provides a clue to why scientists are fascinated by problems in normal research. Although the results are precisely predictable and may not be interesting, the methods to achieve these results remain in question. Driving normal research problems to a conclusion requires solving complex instrumental, conceptual, and mathematical puzzles. The challenge of these puzzles often constitutes a key factor in sustaining ongoing research for scientists. The terms 'puzzle' and 'puzzle-solver' highlight several themes that have progressively become more prominent in the preceding paragraphs. In the strictest sense, a puzzle refers to a unique category of problems that can serve as a test of proficiency or problem-solving skill. This includes the problems and characteristics of normal science that we need to separate. The issue is not whether the results of puzzles are inherently interesting or significant.