Neural Lie Detection, Criterial Change, and OrdinaryLanguage

See, also, Pardo and Patterson [2].

See, e.g., Hacker [3]; Bennett and Hacker [4]; Murphy and Brown [5]; Morse [6, 7]; Noe [8].

It is worth pointing out that the term “neurolaw” refers to a growing interdisciplinary field of inquiry that explores the relationship between neuroscience and the law. As such, neurolaw is neither an intellectual movement nor is it tied to a certain ideological point of view. Just as some researchers push a revolutionary agenda whereby neuroscience ought to be used to overthrow traditional legal categories (see, e.g., Greene and Cohen [9]), other researchers adopt a much more conservative approach to the relationship between law and neuroscience (see, e.g., Morse [6]). Given this very wide spectrum of views, it is a mistake to identify the overall field of neurolaw with particular positions within the field.

I think the argument could even be made that we have Wittgensteinian grounds for resisting the conventionalism of Pardo and Patterson, but that will not be one of my direct goals in this commentary.

The claim by Joshua Greene and Jonathan Cohen that “you are your brain” [9, p. 1779] is identified by Pardo and Patterson as one of their primary targets. We will unpack Greene and Cohen’s views concerning the relationship between the self and the brain in more detail in §3.

We may sometimes talk about a “happy tooth”—e.g., if we just had an aching tooth repaired—but here we are using “happy” in a very loose way. In a similar way, we may talk about Paige’s “smiling on the inside” as well—but here again, we would be using “smiling” very loosely. Moreover, the criteria we would rely on in trying to ascertain whether Paige really is “smiling on the inside” would themselves be behavioral criteria.

Bennett and Hacker call the principle that is purportedly being violated “the mereological principle.” As they say, “We have bluntly asserted the mereological principle in neuroscience, insisting that it is a logical principle, and therefore not amenable to empirical, experimental, confirmation or disconfirmation. It is indeed a convention, but one that determines what does and does not make sense. Its application—for example, to psychological concepts—could, in principle be changed by stipulation, but not without changing a great deal else, thereby altogether changing the meanings of our words and the structure of the multitude of familiar concepts. For the principle that psychological predicates apply to the animal as a whole and cannot be applied to its parts is held in place by a ramifying network of conceptual connections.” [4, p. 81]. This is an issue that has recently been discussed at length by Noe [8] as well.

See, e.g., Wittgenstein [1, 10].

Pardo and Patterson are careful to point out that they are not suggesting that knowledge “just is the relevant behavior”—since it is clearly possible both to (a) “have knowledge without expressing it,” and to (b) “engage in the relevant behavior without in fact having knowledge.” But if satisfying the behavioral criteria is neither necessary nor sufficient for knowledge, it is unclear why these criteria ought to be exclusively used to delineate what can meaningfully be said about knowledge.

Neuroscience-based lie detection is also sometimes called brain-based lie detection. In this paper, I am simply going to use “neural lie detection” for short.

There are actually at least five distinct methods that are presently being developed that use neuroscience in one form or another for the purposes of lie detection. See Greely [11, p.48] for a discussion of these methods as well as their respective shortcomings. To date, there have been a limited number of peer reviewed studies on neural lie detection. Pardo and Patterson mention Kozol et al. [12] and Langleben et al. [13]. See, also, Davatzikos et al. [14]; Ganis et al. [15]; Langleben et al. [16]; Lee et al. [17]; Mohamed et al. [18]; Nunez et al. [19]; Spence et al. [20].

The most recent study on neural lie detection—and arguably the most promising—is found in Greene and Paxton [21]. Their experimental design addresses several of the most prominent shortcomings of previous attempts to use fMRI for purposes of detecting honesty and deception.

See, e.g., Farah and Wolpe [22]; Garland and Glimcher [23]; Greely [11]; Greely and Illes [24]; Kanwisher [25]; Kittay [26]; Langleben [27]; Moreno [28]; Morse [7]; Phelps [29]; Rakoff [30]; Schauer [31]; Sinnott-Armstrong et al. [32]; Spence [33]. For discussions of neural lie detection in the popular press, see Henig [34]; Narayan [35]; Silberman [36].

I agree with Koethe [40] that “For all the use Wittgenstein makes of the notion of criteria, he offers very little in the way of an explanation of it” (p. 603).

See, e.g., Albritton [41]; Caraway [38, 42]; Chihara and Fodor [43]; Garver [44]; Hollinger [45]; Kenny [46]; Koethe [40]; Malcolm [47]; Putnam [48]; Scriven [49]. For a review of the early literature on the Wittgensteinian notion of criteria, see Lycan [50].

Philosophers and psychologists who work in the nascent field of experimental philosophy often probe precisely these kind of folk intuitions with an eye towards shedding light on first-order philosophical problems. For general introductions to experimental philosophy, see Knobe [51]; Knobe and Nichols [52]; and Nadelhoffer and Nahmias [53].

The general issue I am highlighting here was the motivating issue behind the influential debate between Norman Malcolm and Hilary Putnam concerning the relationship between criteria, ordinary language, and scientific discover. See, e.g., Hollinger [45]; Kenny [46]; Malcolm [47]; Putnam [48]. But since Pardo and Patterson did not frame their criticisms of neurolaw in terms of this salient earlier debate, I will set aside the details for now.

Obviously, language cannot be too fluid. There need to be some rules that stand firm so that others can change. The issue we are talking about here, however, is not about the limits of language’s fluidity. Instead, we are merely interested in whether the criteria of ordinary language are capable of change, expansion, or even fundamental revision.

The complete quote is as follows: “It is not as if there is a you, the composer, and then your brain, the orchestra. You are your brain, and your brain is the composer and the orchestra all rolled together. There is no little man, no ‘homunculus’, in the brain that is the real you behind the mass of neuronal instrumentation” [9, p. 1779].

The main issue I am interested in here is not merely exegetical. As such, my concern is not so much with what Greene and Cohen “really meant” but rather whether Pardo and Patterson have appropriately understood the real thrust of the reductive views they reject.

It is worth pointing out that it is true that ordinary language historically relied heavily—if not exclusively—on behavioral criteria. As such, it is unsurprising that so many concepts have the sorts of criteria highlighted by Pardo and Patterson. However, the issue is not the ubiquity of behavioral criteria when it comes to ordinary language. Rather, the issue is whether we ought to use the present behavioral criteria as the sole and definitive normative guideline for distinguishing sense from non-sense.