1.Scientific Paradigms. Thomas Kuhn's Paradigm shift

The word paradigm has been used in science to describe distinct concepts. The word has come to refer very often now to a thought pattern in any scientific discipline or other epistemological context.

The historian of science Thomas Kuhn gave paradigm its contemporary meaning when he adopted the word to refer to the set of practices that define a scientific discipline at any particular period of time. Kuhn himself came to prefer the terms exemplar and normal science, which have more precise philosophical meanings. However in his book The Structure of Scientific Revolutions Kuhn defines a scientific paradigm as: "universally recognized scientific achievements that, for a time, provide model problems and solutions for a community of researchers".

A Paradigm shift (or revolutionary science) is, according to Thomas Kuhn in his influential book The Structure of Scientific Revolutions (1962), a change in the basic assumptions, or paradigms, within the ruling theory of science. It is in contrast to his idea of normal science.

According to Kuhn, "A paradigm is what members of a scientific community, and they alone, share." (The Essential Tension, 1977). Unlike a normal scientist, Kuhn held, "a student in the humanities has constantly before him a number of competing and incommensurable solutions to these problems, solutions that he must ultimately examine for himself." (The Structure of Scientific Revolutions). Once a paradigm shift is complete, a scientist cannot, for example, reject the germ theory of disease to posit the possibility that miasma causes disease or reject modern physics and optics to posit that ether carries light. In contrast, a critic in the Humanities can choose to adopt an array of stances (e.g., Marxist criticism, Freudian criticism, Deconstruction, 19th-century-style literary criticism), which may be more or less fashionable during any given period but which are all regarded as legitimate.

2.Historical Linguistics. Structural Linguistics

Historical linguistics (also called diachronic linguistics) is the study of language change. It has five main concerns:

1.to describe and account for observed changes in particular languages

2.to reconstruct the pre-history of languages and determine their relatedness, grouping them into language families (comparative linguistics)

3.to develop general theories about how and why language changes

4.to describe the history of speech communities

5.to study the history of words, i.e. etymology.

Modern historical linguistics dates from the late 18th century. It grew out of the earlier discipline of philology, the study of ancient texts and documents dating back to antiquity.

At first, historical linguistics was comparative linguistics. Scholars were concerned chiefly with establishing language families and reconstructing prehistoric proto-languages, using the comparative method and internal reconstruction. The focus was initially on the well-known Indo-European languages, many of which had long written histories; the scholars also studied the Uralic languages, another European language family for which less early written material exists. Since then, there has been significant comparative linguistic work expanding outside of European languages as well, such as on the Austronesian languages and various families of Native American languages, among many others. Comparative linguistics is now, however, only a part of a more broadly conceived discipline of historical linguistics. For the Indo-European languages, comparative study is now a highly specialised field. Most research is being carried out on the subsequent development of these languages, in particular, the development of the modern standard varieties.

Structural linguistics is an approach to linguistics originating from the work of Swiss linguist Ferdinand de Saussure. De Saussure's Course in General Linguistics, published posthumously in 1916, stressed examining language as a static system of interconnected units. He is thus known as a father of modern linguistics for bringing about the shift from diachronic to synchronic analysis.

Structural linguistics begins with the posthumous publication of Ferdinand de Saussure's Course in General Linguistics in 1916, which was compiled from lectures by his students. The book proved to be highly influential, providing the foundation for both modern linguistics and semiotics.

After Saussure, the history of structural linguistics branches off in two directions. First, in America, linguist Leonard Bloomfield's reading of Saussure's course proved influential, bringing about the Bloomfieldean phase in American linguistics that lasted from the mid 1930s to the mid 1950s. Bloomfield "bracketed" all questions of semantics and meaning as largely unanswerable, and encouraged a mechanistic approach to linguistics. The paradigm of Bloomfieldean linguistics in American linguistics was replaced by the paradigm of generative grammar with the publication of Noam Chomsky's Syntactic Structures in 1957.

Second, in Europe, Saussure influenced the Prague School of Roman Jakobson and Nikolai Trubetzkoy, whose work would prove hugely influential, particularly concerning phonology, and the School ofLouis Hjelmslev. Structural linguistics also had an influence on other disciplines in Europe, including anthropology, psychoanalysis and Marxism, bringing about the movement known as structuralism.