The failure of foundationalism was the development of Weltanschauung views of Thomas Kuhn and some philosophers. His book, The Structure of Scientific Revolution, published in 1962, is the most cited book in the twentieth century. Thomas Kuhn introduced incommensurability, normal science and paradigm changes to the philosophy of science in this book.
Incommensurability is used to describe conditions when one is not able to judge and compare the same standards, or have no common standard of measurement. This word originated in the 16th century, from the Latin word ‘incommensurabilis’, in a mathematical sense. According to Brown, both Thomas Kuhn and Paul Feyerabend, introduced incommensurability in the context of mathematics. For instance, in the Pythagoreans theory, the diagonal of a square with magnitude 1 is √2. However, this meaning of the irrational number cannot be expressed exactly, which holds true. Incommensurability, thus, describes the inability to compare unrelated concepts.
Paradigm is defined as a typical example, pattern, or model of something, which can also be expressed as a global view of a theory and methodology of a particular scientific topic. This phrase originated in the late 15th century via the Greek word ‘paradeigma’. Thomas Kuhn claimed that science undergoes a paradigm shift, which is discontinuous. The paradigm shift describes a change in basic assumption in science. Paradigm shift has lead scientists to new approaches in understanding something that was never thought before, and therefore, must not be fully, but to account for subjective perspectives. Thomas Kuhn demonstrated that there are three stages in science, viz. prescience, followed by normal science, and then revolutionary science. This progression of stages occurs when “normal scientists” who are practising “normal science” will develop a particular paradigm through experimentation and study, and this paradigm will be challenged by new observations obtained through further experimentations that falsify the current paradigm. When an overwhelming amount of evidence against the existing paradigm accumulates, a state of crisis begins. Therefore, a new paradigm will have to be developed that overrides the problems and limitations of the pre-existing paradigm in order to solve the state of crisis. This “crisis is resolved when an entirely new paradigm emerges and attracts the allegiance of more and more scientists until eventually the original, problem-ridden paradigm is abandoned”