Nuclear deterrence and the logic of deliberative mindreading☆
Introduction
The computational modeling of “mindreading” (e.g., believing that you believe that there’s a deadly boa in the box, Smith mindreadingly predicts that you will refrain from removing the top) is well-established (e.g., see Arkoudas and Bringsjord, 2009, Bello et al., 2007). However, past success has been achieved in connection with scenarios that, relatively speaking, are both simple and common. Consider for instance the false-belief scenario, which drives both of (Arkoudas and Bringsjord, 2009, Bello et al., 2007); a scenario in which a young child, or the computational agent serving as a simulacrum thereof, must predict where some other agent will look in order to retrieve an object from b. A successful prediction requires that the child believe that the other agent believes that the object is located in b. Everyday life, from toddlerhood to (lucid) senescence, is filled with the need to make such predictions in such two-agent cases, on the strength of such second-order beliefs. You do not need a snake and a box or other contrivances to exemplify the logical relationships: If Jones is standing beside Smith while the latter is cooking a meal, and the former is considerate, Jones will not want to be located so as to block Smith’s removal of now-grilled chorizo from one pan in order to add it to the sauce in another—and the courtesy of Jones inheres in his second-order belief about what Smith believes. In addition, both the number and average syntactic complexity of the formulas required to model such scenarios is relatively small.
Herein, we introduce a new computational-logic framework that allows formalization of mindreading of a rather more demanding sort: viz., deliberative multi-agent mindreading, applied to the realm of nuclear strategy. This form of mindreading, in this domain, is both complex and uncommon: it for example can quickly involve at least formulae reflecting fifth-order beliefs, and requires precise deductive reasoning over such iterated beliefs. In addition, the relevant models and simulations involve three, four, five agents, and sometimes many more. In the nuclear-strategy realm, for example, the better kind of modeling, simulation, and prediction (MSP) that our framework is intended to enable, should ultimately be capable of formalizing, at once, the arbitrarily iterated beliefs of at least every civilized nation on Earth.
Our plan for the present paper: In the next section (Section 2), we use a highly expressive intensional logic , embedded within a turnstyle rubric, to model, in four increasingly robust ways, snapshots taken of a four-agent, real-world interaction relating to nuclear deterrence. (The four agents are idealized representatives of the U.S., Israel, Iran, and Russia.) As we explain, this modeling is undertaken with the purpose of achieving simulations that enable predictions about the future, conditional on what actions are performed before at least the end of the future to be charted. In Section 3, we use and extend our modeling in Section 2 to prove that the U.S.’s applying severe economic sanctions, under certain reasonable suppositions, will not deter Iran from working toward massive first-strike capability against Israel. After taking stock of the eight chief advantages of (= desiderata derived from) our modeling approach (Section 4), we explain that both modern digital and tabletop games, and game and metagame theory, are inadequate as a basis for such modeling (Section 5). Next, we anticipate and rebut a series of objections to our new paradigm (Section 6). Finally, in a brief concluding section, we point toward our ongoing and future work.
Section snippets
The scenario and our model thereof
In this section, we first present our logicist framework, , and then consider increasingly complex models of nuclear deterrence represented in this framework. The first two models are simple, in that their structure is fixed and the only possibility of variation is through adjustment of parameter values. Specifically, there is no provision for incorporating deliberative mind-reading in these two models. The third model builds upon the first two and uses to specify the model, and
A prediction of deterrence failure with supporting proof sketch
We now consider a micro-scenario replete with mindreading in which deterrence fails. For the micro-scenario, let’s assume the following time structure: There are five distinct time-points 〈 t0, t1, t2, t3, t4〉 with the obvious temporal ordering and with T = t4. We also stipulate that these are the only time-points in the game such that:
One scenario under which deterrence can fail, no matter what the U.S. does, is when Iran has irrational beliefs. This can be modeled
Derived desiderata
We are now in position to set out eight desiderata our framework satisfies, but which, as we shall soon see, extant frameworks are unable to, but should.
Informal game theory, briefly
Informal game theory (IGT) is something that you are quite familiar with, or have at least to some degree studied and seen in action. Indeed, if before reading the present paper you have been but a casual student of (let alone a practitioner in) nuclear strategy, you have without question witnessed the application of IGT to such strategy (and indeed more on such application momentarily). IGT subsumes, for example, Nash-equilibrium theory, in connection with games of perfect and imperfect
“But the core computational challenges are Turing-uncomputable!”
We imagine some skeptics responding as follows: “In your approach, prediction is proof-driven, which means that in order to determine whether some initial situation S would lead to an outcome O, one must model S via a set ΓS of formulae, model O via a formula ϕO, and then decide whether ϕO is provable from ΓS. But since you are by design well beyond first-order logic (after all, even your ‘causal core’ of the event calculus employs full-blown FOL), this decision-problem is Turing-undecidable.
Conclusion
The foregoing is admittedly but a quick summary of the first phase of our lab’s foray into at-once rigorous-and-cognitively-detailed modeling and simulation in the realm of nuclear strategy, so as to enable reliable prediction. Our ultimate goal is to provide those in US Defense and Intelligence, and civilian decision-makers with whom they work (as well as their counterparts among the allies of the United States), a logico-computational framework that will allow possible futures to be seen, and
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We owe an immeasurable debt to two anonymous referees and the erudite issue editor for brilliant and spirited comments on and objections to earlier drafts of the paper. In addition, Bringsjord and Sundar G. express their gratitude for financial support provided by the John Templeton Foundation and AFOSR.