Brain-based lie detection and the mereological fallacy: reasons for optimism

There has been much hype about the implications of contemporary developments in neuroscience for the law. Pardo and Patterson are skeptical of this hype. They argue that a good deal of the hype stems from simple philosophical errors and conceptual confusions. In the course of this critique, they offer particular objections to the forensic use of brain-based lie detection methods. Although agreeing with the authors about the need for skepticism and conceptual clarity, this chapter argues that they get things wrong when it comes to their skepticism of brain-based lie detection. This is for three reasons. First, in their critique they focus too heavily on the problems associated with the more speculative and less empirically grounded fMRI-based methods, not enough on the more robustly grounded EEG-based methods. Second, when focus is switched to these methods, their main philosophical critique of the use of neuroscience in law the neurolaw mereological fallacy has much less bite. And third, they neglect to address the merits of brain-based lie detection methods relative to existing methods for inferring what a witness does or does not believe. When these three critiques are factored in, the future looks brighter for this particular use of neuroscience in law.