Neuroscience, Justice and the 'Mental Causation' Fallacy

11 Wash. U. Jur. Rev. 191 (2019)

65 Pages Posted: 17 May 2019

Date Written: May 6, 2019


This article takes direct aim at a foundational assumption of modern criminal justice, namely, that there is such a thing as “mental causation,” viz. that criminal acts are caused or influenced by mental states such as intentions or volitions. The pre-scientific supposition that mental states can cause criminal acts is the primary basis for holding that people “deserve” to suffer punishment and, as such, is the most serious barrier to acceptance of neuroscience in criminal justice reform. However, this key justification for modern criminal justice practices is premised on a logical fallacy and is ripe for review.

A growing body of neuroscience evidence shows that human behavior, like that of all other animals with brains, is produced by observable physiological activity in the brain and central nervous system — all in accordance with ordinary physical laws. Beyond these ordinary physiological interactions and processes, no hypothesis of mental causation is required to causally explain behavior. Everything a person does is the result of chains of causation originating outside the person’s body and far back in time.

Despite the evidence, neuroskeptics insist that intentions, reasons and other mental states can play a causal role in producing human behavior. The evidentiary case for mental causation turns out, however, to be premised on a well-known logical fallacy, post hoc ergo propter hoc. Meanwhile, based on the best explanation of all the evidence and data, mental causation almost certainly cannot and does not occur. Therefore, if mental causation is indeed the basis on which offenders are deemed to be responsible and to deserve suffering as punishment, the case for criminal responsibility and current punishment practices is fatally defective.

To be sure, society will likely always need to use coercive measures to deal with individuals who pose dangers and risks that are too socially intolerable to allow. The findings of neuroscience suggest, however, that these measures should be justified on bases that do not presuppose that offenders “deserve” suffering due to mental causation. Even while coercive measures to protect public safety are a practical and moral necessity, their nature and quality may be very different if they no longer are predicated on the premise that people “deserve” to suffer hardship, misery and deprivation purposely inflicted by the state.

Suggested Citation

Humbach, John A., Neuroscience, Justice and the 'Mental Causation' Fallacy (May 6, 2019). 11 Wash. U. Jur. Rev. 191 (2019), Available at SSRN:

John A. Humbach (Contact Author)

Pace University School of Law ( email )

78 North Broadway
White Plains, NY 10603
United States
(914) 422-4239 (Phone)
(914) 422-4015 (Fax)


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