Habermas bases his philosophy on the centrality of language as the medium of rationality and sociality. In doing so, he firmly situates himself against the prevailing philosophy of consciousness, as espoused by Husserl and others around the turn of the twentieth century. Whilst he agrees with the general positivist theory of the natural sciences, Habermas refutes the extension of positivism into areas traditionally seen as the domains of the social and cultural sciences. Contrary to Dilthey’s theory of empathy, Habermas outlines a hermeneutic conception of the social and cultural sciences, in which language is the medium of cognition. The hermeneutic conception states that knowledge about humans as objects are statements about facts, facts that have been pre-constituted by the pragmatic motivations of human beings. The ordering of the world of social action is effected by the shared medium of language, thus language is the primary repository of the facts with which the social and cultural sciences are concerned.
Habermas argues that positivism misses out this prior conceptualisation of facts as social norms; in other words, positivism models knowledge and explanations according to law-like regularities, but these models are of little use when applied to the porous and flexible norms generated in social and cultural life. Thus, Habermas opposes positivism in these domains, instead asserting the essentially historicised and non-universal character of the concepts of social sciences. In this way, the fundamentally social character of knowledge is revealed, and Habermas builds this social character into his model of knowledge, which is based upon three aspects: manipulative/strategic, understanding and emancipatory.
Modern societies tend towards objectivism, which according to Habermas is an alienated understanding of science and society resulting from obscuration of the social and pragmatic character to which they owe these interests. As such, the communicative and ethical interests of society are subordinated to the imperatives of the technologies that control our economic and political life. It is the responsibility of philosophy to critique this ideology, supplanting objectivism with a theory of knowledge that emphasises the intersubjective nature of human interaction. This sort of engagement realises understanding and agreement dialogically, as opposed to the monological discourse that is characteristic of the natural sciences. This kind of communicative understanding would also be capable of grounding ethical relationships, for there is a recognition of identity and difference built into the process of dialogical engagement: I recognise you as another I. Consequently, recognition demands a symmetry in transaction, which is defined by norms that both conversational participants understand and acknowledge. This ideal speech situation can be extended to set the terms for wider social and ethical relationships. Because ‘all speech is oriented toward the idea of truth’ and ‘this idea can only be analysed with regard to a consensus achieved in unrestrained and universal discourse’, the ideal speech situation and the symmetries it entails amount to ‘a linguistic conceptualisation of what are traditionally known as the ideas of truth, freedom and justice’.
From the publication of Knowledge and Human Interests in 1972, to the publication of The Theory of Communicative Action nearly ten years later in 1981, Habermas was concerned with developing an empirical basis for the philosophical claim to universality and rationality. To a degree, Habermas sets aside the earlier theory of cognitive interests in favour of a postmetaphysical approach to reconstructing the shared competences and normative presuppositions that are necessary for actors to participate in acts of communication, discourse and inquiry. The postmetaphysical approach is weakly transcendental, insofar as it is reconstructive; however, it is also weakly naturalist, insofar as the practices it aims to reconstruct are consistent with empirical theories of the natural evolution of the species. The continuity with Knowledge and Human Interests lies in the tripartite model of knowledge, which is modified in The Theory of Communicative Action. So, cognitive instrumental rationality (manipulative/strategic) is still to do with the search for truth, the realisation of the goals of action, and its rational character is expressed in the claim to universal validity. Justification to others (understanding) is now to do with bringing one’s conduct under norms that are valid for others, and less to do with the normative aspect of understanding others. Emancipation now has to do with public avowals of personal attitudes and feelings, rather than particular assertions of right. The subjective character of emancipatory knowledge is retained in Habermas’s use of such phrases as ‘inner’ and ‘subjective states’. Emancipatory knowledge is also apparently intended as the validity claim that will cover the areas of art and symbolism.
All three validity claims are modes of communicative action, thus the theory is a theory of argumentation, which establishes the validity of argument types in a strong normative sense. The process of argumentation also imparts a performative character to the social science that is doing the inquiry.
 Positivism is philosophy of science based on the view that in the social as well as natural sciences, data derived from sensory experience, and logical and mathematical treatments of such data, are together the exclusive source of all authentic knowledge. (Wikipedia)
 At the beginning of the 20th century, empathy understood as a non-inferential and non-theoretical method of grasping the content of other minds became closely associated with the concept of understanding (Verstehen); a concept that was championed by the hermeneutic tradition of philosophy concerned with explicating the methods used in grasping the meaning and significance of texts, works of arts, and actions. (For a survey of this tradition see Grondin 1994). Hermeneutic thinkers insisted that the method used in understanding the significance of a text or a historical event has to be fundamentally distinguished from the method used in explaining an event within the context of the natural sciences. This methodological dualism is famously expressed by Droysen in saying that “historical research does not want to explain; that is, derive in a form of an inferential argument, rather it wants to understand” (Droysen 1977, 403), and similarly in Dilthey’s dictum that “we explain nature, but understand the life of the soul” (Dilthey 1961, vol. 5, 144). Yet Droysen and authors before him never conceived of understanding solely as an act of mental imitation or solely as an act of imaginatively “transporting” oneself into the point of view of another person. Such “psychological interpretation” as Schleiermacher (1998) used to call it, was conceived of as constituting only one aspect of the interpretive method used by historians. Other tasks mentioned in this context involved critically evaluating the reliability of historical sources, getting to know the linguistic conventions of a language, and integrating the various elements derived from historical sources into a consistent narrative of a particular epoch. The differences between these various aspects of the interpretive procedure were however downplayed in the early Dilthey. For him, grasping the significance of any cultural fact had to be understood as a mental act of “transposition.” Understanding the meaning of a text, an action, or work of art requires us to relate it to the primary realm of significance; that is, our own mental life accessible through introspection. (See for example Dilthey 1961, vol. 5, 263-265). Even though Dilthey himself never used the empathy terminology, his position certainly facilitated thinking about understanding as a form of empathy. No wonder then, that at this time the concepts of empathy and understanding were used almost interchangeably in order to delineate a supposed methodological distinction between the natural and the human sciences. (See Stueber 2006 for a more extensive discussion).
Ironically, the identification of empathy and understanding and the associated claim that empathy is the sole and unique method of the human sciences also facilitated the decline of the empathy concept and its almost utter disregard by philosophers of the human and social sciences later on, in both the analytic and continental/hermeneutic traditions of philosophy. Within both traditions, proponents of empathy were—for very different reasons—generally seen as advocating an epistemically naïve and insufficiently broad conception of the methodological proceedings in the human sciences. As a result, most philosophers of the human and social sciences maintained their distance from the idea that empathy is central for our understanding of other minds and mental phenomena. Notable exceptions in this respect are R.G. Collingwood and his followers, who suggested that reenacting another person’s thoughts is necessary for understanding them as rational agents (Collingwood 1946, Dray 1957 and 1995). Notice however that in contrast to the contemporary debate about folk psychology, the debate about empathy in the philosophy of social science is not concerned with investigating underlying causal mechanisms. Rather, it addresses normative questions of how to justify a particular explanation or interpretation. (http://plato.stanford.edu/entries/empathy/)
 Objectivism, in this context, is an alternative name for philosophical realism, the view that there is a reality, or ontological realm of objects and facts, that exists independent of the mind. Stronger versions of this claim hold that there is only one correct description of this reality. If it is true that reality is mind-independent, then reality might include objects that are unknown to consciousness and thus might include objects not the subject of intentionality. Objectivity in referring requires a definition of truth. According to metaphysical objectivists, an object may truthfully be said to have this or that attribute, as in the statement “This object exists,” whereas the statement “This object is true” or “false” is meaningless. For them, only propositions have truth-values. Essentially, the terms “objectivity” and “objectivism” are not synonymous, with objectivism being an ontological theory that incorporates a commitment to the objectivity of objects. (Wikipedia)
 In his various essays on empirical truth, Habermas usually regards propositions as the truth-bearer: in making an assertion, “I am claiming that the proposition [Aussage] that I am asserting is true” (1971/2001, 86; cf. 2003a, 249ff). In his early treatment, however, he immediately equated empirical truth with ideal justifiability—the consensus theory of truth mentioned above. According to that theory, the “truth condition of propositions is the potential assent of all others”; thus “the universal-pragmatic meaning of truth…is determined by the demand of reaching a rational consensus” (1971/2001, 89; cf. 86). Such formulations suggest that Habermas equated the meaning of truth with the outcome of a universal, rational consensus, which he understood in reference to the ideal speech situation (ibid., 97–98). However, he soon saw the difficulties with consensus theory, and he never allowed “Wahrheitstheorien” (1973a), his main essay on the consensus theory of truth, to appear in English. Like the “epistemic” theories of truth that link truth with ideal warranted assertibility (e.g., Hilary Putnam, Crispin Wright), consensus theory downplays the justification-transcendent character of truth (2003a, 250–52). (Stanford Encyclopaedia of Philosophy)
 Some commentators also describe this transitional period as Habermas’s ‘linguistic turn’, as he comes to use speech act theory as the basis for a conception of communicative competence. Formal pragmatics, for instance, is the model for on of the reconstructive sciences, which aim to theoretically explicate the intuitive know-how underlying our basic abilities to speak, act and judge etc. The reconstructive sciences do not yield necessary knowledge in the manner of Kant, however; rather, the knowledge that they reveal is hypothetical, empirical and fallible. They nevertheless raise universal but defeatable claims about practical reason.