A concept suggested by Anthony Giddens as a way of analyzing the relationship between structures and actors. The relationship between structures and actors involves intersubjective understanding and meaning. Structures do constrain actors, but actors can also transform structures by thinking about them and acting on them in new ways.

In Realism, anarchy means absence of a higher authority above states to make and enforce rules in the international system.

Morgenthau’s version of realism, which was later labeled as classical realism, argues that the desire for more power is rooted in human nature.

He suggested that “political realism believes that politics, like society in general, is governed by objective laws that have their roots in human nature”

Classical realism was attacked by other theoretical approaches like neoliberalism, feminism and critical theory. However, the most influential critique came from other realists. Kenneth Waltz became the leading proponent of a new version of realism labeled neorealism (also called structural or systemic realism).

According to Waltz, a scientific IR theory must focus on the international system not on the internal characteristics or leaders of states. Waltz developed a systemic theory in which he diverged from classical realism on the causes of state behavior in the system.

For neorealism, why states continuously seek power has little to do with human nature. Neorealism explains why states want more power with reference to the structure of the international system. While classical realism mainly focuses on state leaders and their decisions, neorealism, by contrast, emphasizes the structure of the international system that is external to the actors, in particular the relative distribution of power. “Leaders are relatively unimportant because structures compel them to act in certain ways. Structures more or less determine actions”

Constructivism entails a wide range of theoretical perspectives whose common denominators include “an emphasis on the importance of normative as well as material structures, on the role of identity in shaping political action and on the mutually constitutive relationship between agents and structures”

In terms of epistemology and methodology, constructivism can be divided into three main categories: neoclassical, postmodern and naturalisticconstructivism.

Neoclassical constructivists incorporate values, norms, and other ideational factors into their theorizing, but “they do not reject the canons of science, standards, and methodologies for testing hypotheses or propositions”.

Postmodern constructivists, on the other hand, “reject the conventional epistemology of social science. They emphasize instead the linguistic construction of subjects, resulting in ‘discursive practices’ constituting the ontological or foundational units of reality and analysis”

Naturalistic constructivism, which is mainly associated with the writings of Alexander Wendt, defines IR as part of the social sciences, and puts more emphasis on the intersubjective aspects or structures of social life.

In terms of the levels of analysis, constructivism can be categorized under three headings: systemic, unit level and holistic constructivism. It should be remembered that all variants of constructivism hold that social structures are as important as material structures that social structures have not only regulative effect but also constitutive effect on actor identities and interests, and that agents and structures are mutually constitutive.

Alexander Wendt makes a distinction between corporate and social identities of states. Corporate identity (personal identity in psychology) refers to the intrinsic, self-organizing qualities that constitute actor individuality. This type of identity generates four basic interests: 1) physical security 2) predictability in relationships to the world 3) recognition as an actor by others 4) economic development. Social identity, on the other hand, is defined as a set of meanings that an actor attributes to itself as a social object while taking the perspective of others, that is, as a social object.

Neorealism holds that state identities and interests are givens. In the anarchical international system, states must acquire egoistic identities and interests. Constructivism, on the other hand, argues that states acquire identities through social interaction; and as a result, state identity becomes endogenous to interaction among states.This is contrary to neorealism which argues that states start interaction with already acquired egoistic identities. This neorealist argument has also important implications for state interests, which are assumed to be also egoistic. Constructivism, on the other hand, assumes that state interests are not determined independently from state identities. In other words, identity is the basis of interests; states first acquire their identities through social interaction and then determine what their interests are. If states’ identities change, then actors’ perspective on certain situations may also change, which may prompt a redefinition of interests.

Instead of focusing on the external, which is international domain, unit-level constructivists concentrate on the relationship between domestic social and legal norms and the identities and interests of states, the very factors bracketed by Wendt.

Holistic constructivism provides more useful tools to explain international change, which was obscured by systemic constructivism. By integrating the corporate and social identities of states into a unified approach, it can easily demonstrate the causes and consequences of changes at both levels.

Inayatullah and Blaney, for example, criticize Wendt for ignoring actors in the pre- social world. They argue that actors construct a sense of self and an understanding of others long before interaction, and they also bring ideas, purposes, intentions, and images to interaction.

Intersubjectivity, a term originally coined by the philosopher Edmund Husserl (1859–1938), is most simply stated as the interchange of thoughts and feelings, both conscious and unconscious, between two persons or “subjects,” as facilitated by empathy.