Mens rea or "guilty mind" is the mental element of a person's intention to commit a crime; or knowledge that one's action or lack of action would cause a crime to be committed. It is a necessary element of many crimes.

Consciousness is a tricky concept, but most/all of us recognise it in ourselves. It is uncertain exactly how much effect it has on our behaviour, with the famous Libet experiments indicating that in some situations at least it may not be involved in decision making that is otherwise assumed to be conscious. One thing we can agree on is that it is a function of the higher brain, the cerebrum, rather than the lower and more primitive parts of the brain that control things like our heart.

Does a Mens rea need to be a conscious guilty mind to be found responsible for a crime, or does an unconscious mind have the capacity to be guilty?

The case that I was thinking about was abortion, and the criminal liability that between elective and spontaneous abortion. If we regard the implications of the spontaneous abortions that occur following traumatic events, and we assumed that certain currently unknown scientific facts were determined:

  • Consciousness does have an effector role on behaviour
  • The spontaneous abortions that occur following traumatic events are mediated by the brain stem, ie. defiantly in the subconscious part of the brain
  • This effect can be triggered consciously, perhaps by thinking about stressful things every few hours for a few days

Given that causing an abortion is illegal in the jurisdiction considered, what would constitute a guilty mind in this situation? An abortion triggered by an extraneous stress (such as 9/11 as in the study), because the mind was involved? An abortion triggered by an internal stress, perhaps the decision to change jobs or move house? An abortion triggered by intentional stress, generated for the purpose of causing the abortion?


2 Answers 2



If a defendant ... can show that they committed a crime as the result of an involuntary act they may be able to plead the defence of automatism.

Note that:

It is up to the jury to decide whether the defence is made out and that the defendant was acting involuntarily due to an external factor.


The mind is not the brain

Legally, that is. Scientifically, there is no mind, only brain.

Science and law are different domains of human knowledge. Like cattle ranching and modern dance. The rules of one do not apply in the domain of the other.

Notwithstanding, where mens rea is a requirement of a criminal act (which is not always) the acts rea is also required.

I can wish you were dead for asking such a stupid question but unless and until I take some definite act towards that end, I’m not guilty.

Only kidding, I think the question is fine: I wish you were dead because I’m a psychopath.

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    I am not sure I understand this. In all the examples I give the abortion occurs, that is the act. The question is whether this act being initiated by the brainstem (subconscious) or the cerebrum (conscious) influences the legality of the act.
    – User65535
    May 10, 2022 at 12:57
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    The point is that the abortions in the study, that occurred in California as a result of the stress from 9/11, and occurred selectively depending on the sex of the child, did have human intervention. It was not conscious (it may well be purely hormonal, we do not know), but it was certainly initiated by the mother (the foetus would not be aware of 9/11).
    – User65535
    May 10, 2022 at 13:02
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    We do not know the details, but this occurred in the 2nd and 3rd trimesters so it would have involved a reaction of the uterine wall to the placenta causing detachment and then the physical expulsion of the foetus. This may (I would say probably) be an interaction of stress hormones with those that maintain pregnancy, but could involve neuronal activety. This is relatively new science, it was this study that proved the effect is caused by abortion rather than conception, it had previously been reported during wars that did not have such a defined timepoint.
    – User65535
    May 10, 2022 at 13:08
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    Overt meaning "done or shown openly"? The expulsion would certainly be that, I suspect the bleeding and pain involved in the whole process could make everything overt.
    – User65535
    May 10, 2022 at 13:10
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    But if you subconsciously cut yourself, and I see it, that is overt.
    – User65535
    May 10, 2022 at 13:15

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