Kuhn characterizes most "normal science" as something he likes to refer to as "mop-up work". For him, "normal science" means research firmly based on one or more past scientific results, results that a particular scientific community recognizes for a time as providing the basis for its future practice. (Kuhn, page 10) In other words, he is talking about theories, which serve as building blocks for future research. These theories are chronicled in elementary and college science textbooks that thoroughly explain the body of the accepted theory, describe many or all of its successful applications along with any observations or experiments performed. These results must share two very special characteristics, the first is that they must be unique enough to attract a group of scientists away from competing modes of scientific activity and that they are also open to leaving all different kinds of problems for future groups of scientists and others . their students to research and solve. These results that satisfy the two requirements are called paradigms. Students study these paradigms to become members of a particular scientific community in which they eventually wish to practice. Very rarely is there disagreement about the foundations of specific paradigms as students learn from researchers who have learned from the foundations of their field. Therefore, all students and researchers whose research is based on the same paradigm must commit to the same rules and standards for scientific practice. But how do paradigms arise? The first scientific investigation begins with a random collection of facts, then different researchers dealing with the same phenomena describe and interpret them in different ways...... halfway through the article...... they have developed their idea and they focused instead on a new change, the Copernican system. This was a good example of how scientists continued to try to study within their paradigmatic dimensions, but instead of discovering more normal science, anomalies were discovered that broke their old scientific tradition. As stated earlier by Kuhn, as a new paradigm gains fame, older paradigms lose members, and their ideas and hypotheses are eventually completely forgotten. This is what Kuhn means by “mop-up work,” and how scientists strive to continue research to expand scientific findings that the community has deemed worthy or particularly revealing. New and unsuspected phenomena and anomalies are impossible to undiscover, introducing problems with the paradigm criterion and forcing scientists to possibly change their perspective on things, over time possibly resulting in a new paradigm.