Page 24 - 《国际安全研究》2021年第5期

超越“确保摧毁”：核武器数量、承诺可信度与核威慑原理

争爆发的概率，那么核战争的风险 r＝κ×ɛ，对此“稳定/不稳定悖论”指出，ɛ 值
①
的升高/降低会导致κ值的降低/升高。 总之，核层面的稳定会引发常规层面的不
稳定，核层面的不稳定会促成常规层面的稳定。
②
现在假设有 A 和 B 两个有核国家，其中 A 国的核武器数量低于确保摧毁门槛，
并且 A、B 两国都知道这一点。当 A、B 两国发生危机时，B 国显然有发动预防性
打击预先消灭 A 国核武器的动机。A 国当然也能预见 B 国的这一动机，为避免自

己有限的核武器在 B 国的首次打击下被全部消灭或者所剩无几以至于无法对 B 国
造成显著伤害，A 国有动机抢先对 B 国发动先发制人式核打击。 可见，一国核
③
武器数量低于确保摧毁门槛的确会导致战略（核）层面的不稳定，亦即导致常规冲
突升级为核冲突的风险（ɛ）升高。但根据“稳定/不稳定悖论”，ɛ 值升高将导致κ

值降低，核战争风险（r）因此并不必然增加。与之对比，如果 A、B 两国核武器

① Robert Powell, “Nuclear Brinkmanship, Limited War, and Military Power,” International
Organization, Vol. 69, No. 3, 2015, p. 596.
② 对“稳定/不稳定悖论”的形式化证明参见 Robert Powell, “Nuclear Brinkmanship, Limited
War, and Military Power,” International Organization, Vol. 69, No. 3, 2015, pp. 589-626。统计证明参
见 Daniel S. Geller, “Nuclear Weapons, Deterrence, and Crisis Escalation,” The Journal of Conflict
Resolution, Vol. 34, No. 2, 1990, pp. 291-310; Robert Rauchhaus, “Evaluating the Nuclear Peace
Hypothesis: A Quantitative Approach,” The Journal of Conflict Resolution, Vol. 53, No. 2, 2009, pp.
258-277; Matthew Kroenig and Robert F. Trager, “Nuclear Stability and Conventional Conflict,”
manuscript, October 28, 2015, http://www.roberttrager.com/Research_files/KT2012.pdf; Bryan Early
and Victor Asal, “Nuclear Weapons, Existential Threats, and the Stability–Instability Paradox,” The
Nonproliferation Review, Vol. 25, No. 3/4, 2018, pp. 223-247。关于中美、印巴等有核国家安全关系
进程符合“稳定/不稳定悖论”的论述，参见 Joshua Rovner, “Two Kinds of Catastrophe: Nuclear
Escalation and Protracted War in Asia,” Journal of Strategic Studies, Vol. 40, No. 5, 2017, pp. 696-730;
S. Paul Kapur, “India and Pakistan’s Unstable Peace: Why Nuclear South Asia is Not Like Cold War
Europe,” International Security, Vol. 30, No. 2, 2005, pp. 127-152; Dinshaw Mistry, “Complexity of
Deterrence among New Nuclear States: The India-Pakistan Case,” in T. V. Paul, Patrick M. Morgan and
James J. Wirtz, eds., Complex Deterrence: Strategy in the Global Age, Chicago: The University of
Chicago Press, 2009, pp. 183-203; Evan Braden Montgomery and Eric S. Edelman, “Rethinking
Stability in South Asia: India, Pakistan, and the Competition for Escalation Dominance,” Journal of
Strategic Studies, Vol. 38, No. 1-2, 2015, pp. 159-182。中国战略界对中美危机稳定性的理解也与“稳
定/不稳定悖论”的逻辑相吻合，参见 Fiona S. Cunningham and M. Taylor Fravel, “Dangerous
Confidence? Chinese Views on Nuclear Escalation,” International Security, Vol. 44, No. 2, 2019, pp.
61-109。当然，也有少数学者从“稳定”的界定和衡量标准角度对“稳定/不稳定悖论”提出质
疑，参见胡高辰、李彬：《稳定—不稳定悖论的批判与美国的安全研究范式分析》，载《国际论坛》
2018 年第 4 期，第 53-54 页。
③ Charles L. Glaser, Analyzing Strategic Nuclear Policy, Princeton, N.J.: Princeton University
Press, 1990, p. 45.

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