1. Introduction

The traditional interrelation of theories in the discipline of International Relations (IR) could essentially be deemed as one of tension: where interaction between theories could only result in either stalemate or supplantation, and where researchers have to be ‘loyal’ to only one particular approach [1-2]. Such an inharmonious relationship between IR theories has arguably impeded the precious room for inter-theory dialogue and fruitful cross-complementation, and has thereby brought significant repercussions to the academic development of the discipline. As a solution to such issue of inharmony, the idea of theoretical pluralism has been actively promoted by scholars such as Yosef Lapid and Patrick Jackson [1,3]. Theoretical pluralism, by accepting the diversity of perspectives and arguments, while contending the interrelation of theories as one of dialogue and conversation, could potentially be seen as a pathway towards the harmonious consolidation of theories, and thereby the further development of IR towards greater comprehensiveness [1].

This essay appreciates the value of theoretical pluralism to IR and aims to make this case by empirically demonstrating the utility of theoretical pluralism in IR. Therefore, on the basis of qualitative analysis, this research adopts a case-study approach to use the empirical example of realism and constructivism to illustrate the utility and value of theoretical pluralism in IR.

This research chooses realism and constructivism as its case study because of two main reasons. The first reason is that they are both highly prominent and influential among IR scholars. Therefore, by showing that even highly prominent theories of realism and constructivism requires coordination instead of isolation to be more comprehensive, this essay may celebrate higher representativeness and persuasiveness. The second reason is that, they share a similar analytical focus (both theories address states’ behaviours and the dynamics behind them) and are both belonged to the tradition of positivism (which means that they are founded on identical epistemology) [4-6]. Hence the paring of them is essentially feasible and of decent analytical value.

The contribution this essay strives to make can be classified into two layers. Microscopically, it contributes to the school of pluralism by empirically showing that pluralist ideas can essentially enable theories to cross-complement each other and generally improve the comprehensiveness of their concepts. Macroscopically, it contributes to the study of research epistemology of IR, which is arguably the core of the discipline’s development.

This essay will progress in four sections. The first and second section will discuss the conceptual limitations realism and constructivism suffers if applied in perfect isolation respectively. Then, the third section will highlight the implications of the discussions in section one and two and therein supports the promotion of theoretical pluralism in IR. Finally, the last section will conclude this research by summing up all the discussions.

2. Realism

2.1. An Overview of Realism

The theory of state realism is foundationally established on three key assumptions, notably: 1) the international community is an anarchic “state of nature”, meaning that it is a zero-sum and self-help environment; 2) states are rational actors that seek to maximise their chance of survival; and, 3) power is the currency states hold to exchange for survival [4,7]. Following these premises, states were deemed unitary actors that sharee the grasp on power and the urge for survival as the central impulses behind their actions [8]. For example, in the realist’s lens, any state would see the military and/or economic buildup of another state as a national security threat, typically because the latter’s disturbance of the existing balance of power has weakened the former’s relative position in the power hierarchy and therein lowered its chance of survival.

Most sub-schools of realism, such as classical realism and structural realism (neorealism), conform to the ontology of power- and survival-primacy, though one branch of the realist family, namely neoclassical realism, attempts to add the varying domestic conditions of different states into the analysis as an additional factor [4,9,10]. Yet, despite the endeavour of neoclassical realists, the works of neoclassical realism have often been critiqued as “ad hoc” and rejected by mainstream realists, and thus the variant of neorealism cannot foundationally alter nor represent the general ontology of realism [11-12].

2.2. Evaluating Realism: Its Incomprehensiveness When Applied in Isolation

Whilst realists see power and survival as the primary reference points for states in determining their behaviour, it can nevertheless be observed that not all cases of international interactions conforme to realism’s conceptualisation. For example, Russia hardly perceives China as a threat, even though China’s aggregate power has risen substantially [13]. In another case, while America responded to China’s nuclear testing in 1964 with suspicion and vigilance, it responded to France’s nuclear testing in 1969 with assistance and support [14-15]. These cases of analytical imprecision indicate that realism inevitably suffers from conceptual limitations when applied in isolation from other theories. Indeed, by seeing states as unitary actors guided merely by the grasp on power and the urge for survival, the account of realism has arguably neglected the role of various other factors, for instance, states’ identity. The importance of identity in shaping states’ behaviour can be witnessed in the two aforementioned events of international interaction. One may essentially point out that Russia did not perceive China as an active threat because the two countries identify each other as cooperating partners instead of competitors. Furthermore, America’s response to China and France’s nuclear programme varied significantly because it identified China as an opponent, but France as an ally. It can be clearly seen at this stage that realism has failed to cover sufficient factors that influence state behaviour, and cannot, therefore, be regarded as a comprehensive account when applied in isolation.

3. Constructivism

3.1. An Overview of Constructivism

The core assumption underlying the school of constructivism emphasises that the world is a “coming into being” rather than a pre-given entity [6,16]. In this way, states, through interactions with each other, form their respective understandings and interpretations of social realities, e.g., distinguishing between “friends” and “enemies”, identifying themselves as belonging to a particular group, and differentiating who are “others” [6, 17-19]. These understandings and interpretations of social realities are all entailed in the respective identities of states [17]. Constructivist scholars argue that identities are important in determining the relationships and interactions between various actors [6]. As Wendt suggests “People act toward objects, including other actors, on the basis of the meanings that the objects have for them. States act differently toward enemies than they do toward friends because enemies are threatening and friends are not” [17].

3.2. Evaluating Constructivism: Its Incomprehensiveness When Applied in Isolation

Similar to realism, whilst constructivists see identity as the primary factor determining states’ behaviour, it can nevertheless be observed that not all cases of international interactions conform to constructivism’s conceptualisation. For example, besides launching a trade war against its competitor, China, the USA has also repetitively attempted to impede the economy of its important ally in Asia, Japan, over the last 50 years [20]. Another example is that, despite a history of more than two decades of conflict, China had nonetheless begun to seek cooperation with the USA by the 1970s [21]. These cases of analytical imprecision indicate that constructivism, like realism, also suffers from conceptual limitations when applied in isolation from other theories. Constructivism has arguably overemphasised the importance of identity as a determinant of state behaviour, and thus overlooked the role of various other factors, for instance, power and survival. Although its influence on state behaviour is not as strong as the realists would posit, it can nevertheless not be downplayed. The two listed events of international interaction show that power and survival are of certain importance for states in decision-making. The USA impeded its ally Japan’s economy to maintain its economic superiority and thereby hegemony, The Sino-Soviet relationship became hostile by 1969 as boarder conflicts waged, it was obvious that China could not maintain hostilities with the two central figures of the Cold War at the same time, and thus had to seek cooperation with the USA to ensure its survival. It can be clearly seen at this stage that constructivism is suffering from a similar problem as realism, which is that it has failed to cover sufficient factors that influence state behaviour, and cannot, therefore, be regarded as a comprehensive account when applied in isolation.

4. Implications

Both realism and constructivism, while celebrating a highly influential position in the discipline, are nonetheless suffering from constraints and can hardly provide a comprehensive account of state behaviour if applied in perfect isolation. Realism focused too much on the influence of power and survival on state behaviour, which consequently resulted in the neglection of national identity. Conversely, constructivism focused too much on the influence of national identity on state behaviour and, as a result, overlooked states’ concerns about power and survival. This evaluation of realism and constructivism presents an interesting implication that a rich potential for complementarity exists between them, notably because the factors that realism lacks awareness are precisely that of constructivism’s speciality, and vice versa. If the two theories engage in dialogue with each other under the light of theoretical pluralism and therein cross-complement each other, the existing potential of complementarity can then hopefully be utilised. Typically, instead of seeing the logic behind states’ behaviour as a singly-factored mechanism with either the concern of power and survival or identity acting as its sole determinant, it can alternatively be seen as a dually-factored mechanism in which power and survival concerns and identity can act as its determinants simultaneously. By indicating a dually-factored mechanism, this essay does not intend to claim that the two factors are necessarily influencing states’ behaviour fifty-fifty, instead, it contends that the respective influence of two factors on states’ behaviour may vary from case to case. This act of theoretical cross-complementation allows realism and constructivism to cover each other’s shortcomings with its own strengths, and thereby enhance the overall comprehensiveness of theoretical understandings. It is essentially on these premises that this essay argues that theoretical pluralism is of high utility and value to IR and should therefore be applied further in the discipline.

5. Conclusion

This essay attempts to further promote the idea of theoretical pluralism in the discipline of IR, and it attempts to make this case by empirically demonstrating the utility of theoretical pluralism in IR through the cases of realism and constructivism. Realism and constructivism, though highly prominent in the discipline, are nonetheless unable to provide a comprehensive account of state behaviour if applied in perfect isolation. The comprehensiveness of understanding state behaviour can be greatly enhanced if the two theories can be applied harmoniously in conjunction under the light of pluralist ideas, which then stresses the utility and value of theoretical pluralism and supports its promotion in IR.

This essay acknowledges that its research output is indeed not without limitations, typically in terms of the lack of diversity and coverage of case studies. Given the constrained scope of its research, this essay is only able to apply the integrated model to one case study (i.e., the pair of realism and constructivism), which might indicate a lack of diversity and selective bias. Henceforth, besides welcoming further suggestions, this essay also wishes that its limitation may be reduced should any future studies illustrate the value of theoretical pluralism for IR with reference to more theoretical schools of the discipline.