[Abstract] Introducing quantum theory into social sciences research has been a new phenomenon of interdisciplinary endeavor. Based on quantum theory and its major conceptions, it intends to adopt a quantum thinking that is different from a traditional one. The world represents itself as one of wholeness, discontinuity, complex causation, and uncertainty if it is understood through the quantum thinking. This thinking-shift brings about in international studies a“quantum turn”, which encourages the close study of relativity, consciousness, as well as uncertainty in international relations. Diplomacy, as a constitutive part of interstates interactions, possesses quantum features in its performances, as it is shown that there exists the entanglement of competition and cooperation on national levels, the superposition of diplomacy practice, and the integrity of diplomatic strategies. This does not mean, however, that the quantum thinking is a substitute for the traditional one, but rather it invites to add a new way of cognitive activity in international studies. So its significance cannot be underestimated both theoretically and empirically.
[Keywords] quantum theory; quantum thinking; international relation studies; diplomacy
of European Union