A staple of any good argument, be it a philosophical argument, a public policy position, or even a debate about the relative merits of daily exercise, is clarity. What clarity accomplishes is both good and bad for arguments. A clear argument draws its power, in part, from the compelling nature of the connections made in the course of the argument. Likewise, clarity can reveal the flaws in an argument, leaving the proponent of the position to either concede defeat or reformulate the argument in better terms.

One of the principal virtues of philosophy (as method) is the relentless search for flaws—clear or hidden—in argument. As every college student knows, there are multiple fallacies. Fallacies such as the fallacy of composition, appeal to authority, and begging the question are quotidian features of daily newspapers and faculty lounges. In addition to these relatively well-known, common forms of fallacious argument, there are more sophisticated and more difficult argumentative errors. It is with these latter forms of argument that we focus in this chapter. The fallacies we focus on are logical or philosophical in nature.

One might rightly ask what is a “philosophical fallacy”? There are errors in computation, mistakes in reasoning, but what is a “philosophical error”? Throughout this paper, we answer this question by carefully scrutinizing the claims made by a broad spectrum of authors who take the view that matters of mind are best understood or explained as neurological events. The mantra for this group is “your mind is your brain.” Adopting this view leads to the philosophical errors we highlight. These errors are logical or philosophical in the sense that the claims made take language beyond “the bounds of sense”. Claims transgress the bounds of sense when they apply terms expressing concepts to contexts in which they do not apply—without stipulating or presupposing a new meaning for the term. So, for example, we take issue with the idea that a rule or norm can be followed “unconsciously.” The very idea of “following” a rule means that one is cognizant of it and ready to invoke it in any context that implicates the rule. Through example and exegesis, we show why the idea of “unconscious rule following” makes no sense.

Before advancing our arguments, we wish to dispel a potential confusion at the outset. Our discussion of problematic conceptions of mind and other mental attributes may suggest to some readers that we are setting up a classic dualist versus materialist discussion, with the neuroscience proponents falling on the materialist side. This is not so. Indeed, as we will discuss, the putative dichotomy is a principal source of the problems we survey. Cartesian dualism—with its picture of mind as an immaterial substance, independent of but in causal relation with the body—is typically set up as the foil in many neuroscience discussions. For example, in introducing the journal Neuroethics, Neil Levy writes that “Cartesian (substance) dualism is no longer taken seriously; the relation between the brain and the mind is too intimate for it to be at all plausible… [N]euroscientific discoveries promise… to reveal the structure and functioning of our minds and, therefore, of our souls.” (Levy 2008, p. 2) Likewise, in discussing the implications of neuroscience for jurisprudence, Oliver Goodenough writes that the “Cartesian model… supposes a separation of mind from the brain”, whereas models of mind for “a nondualist like myself” are “what the brain does for a living.” (Goodenough 2000–2001, pp. 431–432) The dichotomy between dualism and mind-as-brain is a false one. Moreover, materialists like Goodenough are too Cartesian—he, like many neuroscientists and neurolaw scholars keep the problematic Cartesian structure in place by simply replacing the Cartesian soul with the brain.

Rather than arguing about where the mind is located (e.g. in the brain or elsewhere) we need to step back and contemplate whether this is the right question to ask. First, notice that the question of the mind’s location presupposes that the mind is a kind of “thing” or “substance” that is located “somewhere” (e.g. in the body). Why must this be so? Our answer is that it need not be, and is not. An alternative conception of mind—the one that we contend is more plausible—is as an array of powers, capacities, and abilities possessed by a human being. These abilities implicate a wide range of psychological categories including sensations, perceptions, cognition (i.e. knowledge, memory), cogitation (i.e. beliefs, thought, imagination, mental imagery), emotions and other affective states (i.e. moods and appetites), and volition (i.e. intentions, voluntary action).

To be clear, we do not deny that a properly working brain is required for a person to exercise the diverse array of powers, capacities, and abilities the exercise of which we collectively identify as mental life. Although neural activity is required for a human being to exercise these powers, capacities, and abilities, neural activity alone is not sufficient. The criteria for their successful exercise are not a matter of what is or is not in the brain. These criteria—which are normative in nature—are the basis for our attribution of mental attributes. To outline briefly one of the examples that we will explore below, consider what it means to “have knowledge”. We believe that “knowing” is not (just) having a brain in a particular physical state. Rather, it is having the ability to do certain things (e.g., to answer questions, correct mistakes, act correctly on the basis of information, and so on). Thus, if behavior of various sorts, and not brain states, constitutes the criteria for “knowing,” then it will make no sense to say that knowledge is “located” in the brain. The same is true for other psychological predicates—and for the mind itself. So, to the question, “what is the mind: an immaterial substance (Descartes) or the brain?” we answer “neither”. To the question, “where is the mind located: in the brain or in a non-spatially extended realm (Descartes)?” we answer “neither.” Human beings have minds, but minds are not substances located somewhere within their bodies.

We recognize that our claims may initially strike those operating within the dualist versus mind-as-brain dichotomy as unorthodox. Thus, to undermine what we see as entrenched but problematic presuppositions underlying many neurolaw claims, we proceed deliberately and carefully. We begin our argument by introducing an important methodological distinction between conceptual and empirical questions. In the context of neuroscience research, empirical claims are those that are amenable to confirmation or falsification on the basis of experiments or data. By contrast, conceptual questions concern the logical relations between concepts. We explain why the questions of what the mind is and what the various psychological categories under discussion are (e.g. knowledge, memory, belief, intention, decision making), are conceptual rather than empirical questions.

Given that these are conceptual issues, we next discuss the distinction between criterial and inductive evidence. This issue concerns the inferences that may be drawn from a body of evidence (neuroscience research) regarding various capacities and their exercise. We then turn our attention to philosophical problems that arise with claims regarding norms. Again, the critique we offer is philosophical in nature. The topics of unconscious rule following and interpretation are staples of the philosophical literature. We show why the approaches of several neurolegalists to these issues engender conceptual confusions.

We then take up the question of knowledge. Knowledge is a central concept in law, having a wide range of applications from tort law to criminal law and beyond. We make the case that knowing something to be so is best understood as an array of abilities or capacities and not as a particular state of mind or brain.

The important issue of the relationship between conceptual and empirical claims has, unfortunately, received little direct attention in the current debate over the present and future role of neuroscience in law. Empirical neuroscientific claims, and the inferences and implications for law drawn from them, depend on conceptual presuppositions regarding the mind. As we see it, many of the proponents of an increased role for neuroscience in law rest their case on a controversial and ultimately untenable account of the nature of mind. Although we recognize the need for greater emphasis on and interrogation of the empirical claims regarding neuroscience applications in law, we believe that the fundamental conceptual issues regarding the mind are of equal, if not greater, importance.

Devoted as they are to understanding the physiology of the brain, neuroscientists are principally interested in physical processes. Of greatest interest to neuroscientists are questions regarding neural structures, the functioning of the brain, and the physiological bases for a wide range of mental attributes, including consciousness, memory, vision, and emotion. Scientific explanations, including those of neuroscience, are framed in a language of explanation most readily identified as “empirical”. Grounded in theories and hypotheses, scientific claims are tested by means of experiment. Experimental confirmation or disconfirmation of hypotheses forms the basis of the scientific method.

Empirical and conceptual questions are distinct. We would go so far as to say that they are logically distinct. In addition to their distinct characters, the conceptual relates to the empirical in a certain way: the very success of empirical inquiry depends upon conceptual clarity and coherence. An experiment grounded in confused or dubious conceptual claims can prove nothing.