Literary theory started as soon as literature started developing several centuries ago. According to the recorded history of literature, the Greeks were the first group of people to come up with literary theories. They are the first group to have had criticism of literature in the history of mankind. In the English literature history, literary theory started much later compared to the Greeks literature. It started with the Renaissance. The first theories included the defense of poesy and the Romans theories which emphasized on the content of the literature. This was followed by the Russian Formalism and the New Criticism which started in America. The New Criticism was an English literary school of thought which had a believe that the form and the meaning could not be separated. Later, the hermeneutics school of thought emerged in the literary theory.

The hermeneutics theorist believe in the interpretation of the literature in order to construct what the literature means and that all the parts of the text have to be understood so as to understand the text. This led to the emergence of the structuralism in the 1960s. Structuralism brought about a lot of change in the field of literary criticism and theory. It mainly focuses on language and the structures in the text. It applies linguistics in the study of the text and literature. After the structuralism, emerged the theory of post structuralism which was based on the weaknesses of structuralism (Siddique, Para 1).

Structuralism
This literary theory was developed in the 1960s and was developed according to Ferdinand de Saussure ideas. Saussure had a structural view of language from which structuralism was developed. He developed the ideas of langue and parole. He believed that langue form the structure of the language while parole was clearly seen in the speech. He expressed his ideas in 1916 in his famous book which was known as Course in General Linguistics. His study was based on the study of signs and the way they are used and therefore he called his ideas literature semiotics. He proposed two parts of a sign - that is a signifier which is the sound form of the sign or what is recorded in writing and a signified which is the concept form of the sign. According to his suggestions, the relationship between the two parts of sign is arbitrary. This suggestion has been supported unanimously since signifier and signified are not fundamentally or naturally related. He believed that language is a summation of different signs which have arbitrary relationship. Therefore, the binary opposition relationship of the signs is what gives the meaning. The different in signs in every sentence gives the sentence a meaning. The syntax of words in a sentence or any form of literature gives it a meaning. Therefore, he suggested that a structure of signifying signs makes up a language (McBride, Para 1).

The ideas about signs developed by Saussure revolutionized the understanding of language and were adopted by many scholars of the 20th century not only in literature but also in other disciplines such as science of mathematics and psychology. Structuralism school of thought was developed by the French scholars in the mid 20th century based on the concepts of sign proposed by Saussure. The school of thoughts main attention is how the meaning of a literature is developed. Those who believe in structuralism focus on the structure of the language, the community as well as the psyche rather than focusing on how conscious the author is. It is a theory that looks at how a literature text develops the meaning but not the meaning of the text itself. One structuralist analysis of a text looks at how the arrangements of linguistic structures create unity in a text and the other tries to interpret how the structures and literary forms determine the meaning of a language (Siddique, Para 8).

Structuralism maintains that the meaning can be obtained from the literary text. The meaning is in a language of system of signs and stresses the significance of the text in developing the meaning. By the relationship between signs in a language being arbitrary and only binary, opposition indicates that what another sign in the text is not which leads development of a meaning. Therefore, structuralism suggests that the meaning of the text is within the text and not beyond. The text meaning is determinable and determinate. The language in the text constructs the meaning of the text which means that diachronic study is not necessary in the understanding of the text. However, this criticism suggests that synchronic study of a text is essential in the understanding of the text. The paroles as suggested by Saussure represent the text while the langue is the meaning of the text which is developed from the structures.

According to Newton, structuralism emphasize on a system that make literature into something that is possible and looks at the consideration of author or the history of the text as insignificant in developing the meaning of the text. He suggests that the main aim of literary theories should be explaining how the meaning of the text is developed and not the meaning of the text (Newton, p 83).  Murfin and Ray suggest that literary work has changed its name to text as a result of structuralism. This has been due to its focus on the text and not on the author. Both the reader and the author have internalized codes which are used to express the authors work and the reader can easily decode them to develop the meaning. Therefore, the meaning expressed on the text is not a private experience of the author but is as a result of mutual systems of significance (Murfin and Ray, p 300).  

However, structuralism is not without weaknesses. It has been criticized by some scholars who developed post structuralism. Post structuralism criticized structuralism towards the end of the 20th century by rejecting the theories claim to scientific analysis as well as meaning of a text being determinate and determinable. The primary weakness of the theory is the way it takes language. It does not take it as an individual expression. The theory also has a questionable way in which it conceptualize the relationships between individual members of the community and the communities. The theory attacks language at the most critical point, that is where the linguistic is produced and the actual writing and reading. Critics of structuralism believe that moving away from these ideology moves the language to communication. Structuralism has also been criticized for ignoring dialogue nature of language while focusing on langue. For that reason, Eagleton agued that structuralism has tried to replace the religion of science with ideologies that are as effectual but it has failed. Criticisms of structuralism lead to the development of post structuralism (Eagleton, p 93).

Post structuralism
Post structuralism is ideologies that were developed after structuralism in the 1970s as a reaction against the ideologies of structuralism. It is also centered on the text but does not differentiate the world from the text. Those who believe in post structuralism argue that there is a binary opposition. However, it differs from the previous criticism by suggesting that a signified can have several signifiers. According to post structuralism, there exist binary opposition but they transform and eventually become fluid. Therefore, there is some existence of fluidity between texts which was not suggested by structuralism. This fluidity between text has been referred to as inter textuality by post structuralists.

Post structuralism opposes the structuralist suggestion of possible determinate knowledge. They suggest that words may have many meanings and may lead to propagation of the wrong meaning. Therefore there is a possibility of the text contradicting their structural account as well as their intended meaning. In other words, signifiers can not be absolutely differentiated from signified and a signifier may have several signified. A signified can be seen as a signifier thus forming a long chain which may be unending. The signifiers seem to be intermingling with the signified, text with text and text with the world creating some fluidity. This contradicts the believe by structuralist that meaning is determinate although it is contained in the text. Moreover, post structuralism opposes the rejection of diachronic study of a literature by structuralism.

Deconstructionism is an extension of post structuralism philosophy which supports pluralism of meaning. It believes that meaning is indeterminate and therefore it must be plural. It gives room for varying interpretation of the same literally text. The two theories focus on the reader as where he is viewed as the locus of the competing and contradiction dialogue. Post structuralists argue that any text is a mixture of preexisting texts. The rise of post structuralism school of thought has led to the development of various theories on literature such as feminism, deconstruction in Yale and post modernism among others.

Comparison of structuralism and post structuralism
Structuralism and post structuralism have several differences as well as similarities. Both schools of thought share a common concern on signs and the usefulness of sign systems in the development of meaning. The contribution of both theories in knowledge of literature and culture is unimaginable. Many philosophers in the modern world view post structuralism as a rebellion against the previous theory. However, it is evident that post structuralism is based on the weaknesses of structuralism which did not address comprehensively all the issues. Structuralism is more logical although it focuses on the text. This is because the meaning of the text is derived from observation of the structures and reason.

The main difference in the ideologies of the post structuralism and structuralism is on the philosophical approach of the post structural theory. It suggests that every detail of the text can be questioned which includes the linguistics. The approach is also emotional as compared to structuralism and is more related to the post modernism school of thought. It has been viewed as being born out of the humanism and the structuralism criticisms where the ideas in the previous thoughts were adopted and adapted. It reflects on the structuralism focus on the text while paying less emphasis on the message as well as the liberal humanist approach which focused on the author (Siddique, Para 11).

Scholars who believe in post structuralism ideologies argue that it is historical and believe that structuralism is descriptive. This is based on differences which were proposed by Saussure that study of a test can be diachronic which is historical or synchronic which is descriptive. Therefore, post structuralism gives room for diachronic study while structuralism suggests synchronic as the only study method. Post structuralism focus on the history of the text in the development of the meaning while structuralism argues that the meaning of the text can only be developed from structures of the language in the text. In other words, structuralism focus on the text while post structuralism focus on the reader and his ability to understand the concepts of the culture and the changes in those concepts in order to develop a meaning. Structuralism focus on the meaning of the text as developed by the author but not the meaning as it is developed within the present cultural concepts. However, it is difficult to determine the exact uncertainty distance that exists between the two criticisms because philosophers really dont declare whether they are post structuralists. It has been observed that scholars who were considered structuralists have over the years done works which make them notable post structuralists (Klages, Para 2).

It is clear that post structuralism and structuralism are different schools of thought in literary theory. Structuralism focuses on the structures in the text and their importance in the development of the meaning while post structuralism is based on the weaknesses of structuralism. However, both have had a great contribution in the evolution of literary theory.