When Neurotechnology Erodes Freedom of Thought: The Habeas Cogitationem Writ

[José M. Muñoz is a senior researcher in neurotechnology at the International Center for Neuroscience and Ethics (CINET) in Spain. He is also a board member at the International Neuroethics Society (INS) and an executive member for Ibero-America at the Centre for Neurotechnology and Law (CNL) in the UK.

José Ángel Marinaro has a PhD in legal and social sciences, and is a professor and researcher in neurolaw at Universidad Nacional de La Matanza (UNLaM), and an honorary advisor to the Chamber of Deputies of Argentina.]

Toward the Third Habeas Writ

Habeas corpus (‘you shall have the body’) is a well-known urgent procedural mechanism for protecting the physical/bodily self-determination of citizens in situations such as illegal detention or torture, among others. The Oxford Dictionary of Law defines this mechanism as

[a] prerogative writ used to challenge the validity of a person’s detention, either in official custody (e.g. when held pending deportation or extradition) or in private hands.

This writ, widely used throughout the world, is complemented in various countries by a similar mechanism intended to protect the informational self-determination of citizens regarding their personal data: the so-called habeas data (‘you shall have the data’). This pair of writs is characterized by agility, speed, and absence of unnecessary formalities during the legal process. Furthermore, as can be deduced from the above definition of habeas corpus, although they are usually employed to address state abuse, they can also be leveraged as protective mechanisms against abuse by private parties.

Now, imagine that a lawyer, attorney, or judge has the responsibility to deal with unexpected situations such as the hacking of deep brain stimulation (DBS) devices, the non-consensual collection and/or analysis of brainwaves to obtain criminal confessions (i.e., brain fingerprinting), or the coercive application of brain surgery to inmates in order to prevent aggressive behavior. With recent advances in neuroscience and neurotechnology, it is theoretically possible for legal professionals to be confronted with these types of complex scenarios.

In fact, these types of situations have recently generated landmark court decisions. In August 2023, the Chilean Supreme Court ruled against the American company Emotiv after a user of one of its electroencephalography (EEG) devices filed a constitutional protection appeal alleging that his mental privacy and integrity had been eroded. The court’s decision—the first of its kind in the world—forced Emotiv to delete the plaintiff’s brain data and halted sales of the device in Chile until its compliance with the country’s health and customs requirements is proven.

In view of these novel situations in which neurotechnology may be used to erode fundamental rights related to the brain and mind, it seems essential to discuss the possibility of employing urgent procedural mechanisms to effectively protect these rights. In this regard, we the authors of this piece have developed a broad conceptual and normative proposal for a novel habeas writ specifically designed to safeguard mental self-determination: the so-called habeas cogitationem (‘you shall have the thought’), which we define as

a prerogative writ used to challenge the validity of a neurotechnological interference in a person’s thought process, either in official or private hands.

Safeguarding Cognitive Liberty: Neurotechnology as a Potential Threat to Freedom of Thought

The object of protection of habeas cogitationem (i.e., a person’s thought process) against harmful neurotechnological interferences appeals to an important yet underdeveloped human right: freedom of thought, which is included in key declarations and conventions of international human rights law. For instance, according to Article 18 of the Universal Declaration of Human Rights,

[e]veryone has the right to freedom of thought, conscience and religion; this right includes freedom to change his religion or belief, and freedom, either alone or in community with others and in public or private, to manifest his religion or belief in teaching, practice, worship and observance.

Another important example is Article 13.1 of the American Convention on Human Rights:

Everyone has the right to freedom of thought and expression. This right includes freedom to seek, receive, and impart information and ideas of all kinds, regardless of frontiers, either orally, in writing, in print, in the form of art, or through any other medium of one’s choice.

These two cases show that freedom of thought tends to be understood as closely related to, or even inseparable from, other rights such as the freedoms of conscience, religion, and expression. From the reading of these articles, the idea emerges that it is the behavioral and social manifestation of what people think that is being protected. But what about the internal process of thinking?

The collection and analysis of brain data poses a major challenge to protecting the privacy of the innermost realm of thought, as demonstrated by the fact that this data can be modified in real time and, in some cases, allows re-identifying users despite having been anonymized. Moreover, advances in neurotechnology are increasingly making it possible to obtain highly sensitive information about people’s mental activity. An important example in this regard is the inference of intentions, images, and even linguistic content by means of a technique called brain decoding. It is also revealing—and extremely relevant to the right to freedom of thought—that certain data about brain structure might be associated with people’s political ideology.

Since the beginning of civilization, human norms and laws have been governed by the regulation and protection of behavior, leaving aside the forum internum of thought—quite possibly because it was considered inalienable and, therefore, not in need of protection. Even George Orwell’s almost prophetic novel 1984 reminded us that

[a]sleep or awake, working or eating, indoors or out of doors, in the bath or in bed — no escape. Nothing was your own except the few cubic centimetres inside your skull.

Part 1, Chapter 2; our italics

Advances in neurotechnology suggest the possibility that these few cubic centimeters—and the associated mental activity—may cease to be the exclusive preserve of the individual. Therefore, measures must be promoted to protect and guarantee so-called cognitive liberty, defined by Wrye Sententia as

every person’s fundamental right to think independently, to use the full spectrum of his or her mind, and to have autonomy over his or her own brain chemistry. Cognitive liberty concerns the ethics and legality of safeguarding one’s own thought processes, and by necessity, one’s electrochemical brain states.

Considering this definition, cognitive liberty could be considered an extension or reconceptualization of the right to freedom of thought, which would thus protect not only the behavioral outcomes of thought, but also thought proper. The writ of habeas cogitationem is designed precisely to enforce and provide effective protection for this human freedom, which, for the first time in history, can no longer be taken for granted.

Habeas Cogitationem: The Fundamentals

As aforementioned in this piece, we define habeas cogitationem (‘you shall have the thought’) as

a prerogative writ used to challenge the validity of a neurotechnological interference in a person’s thought process, either in official or private hands.

If we look at the typology of this procedural right, it is classified as a negative constitutional writ—where ‘negative’ means that it is applied only if some action is directed toward the individual—that, as with the two pre-existing habeas writs, entails a swift, agile legal process with barely any formalities. If we focus on its scope of protection, this novel writ is aimed at protecting mental self-determination via the enforcement of cognitive liberty—the extension of the right to freedom of thought that safeguards thought proper. Furthermore, since cognitive liberty can be understood as a prerequisite for other rights aimed at protecting the human brain and mind—often known as ‘neurorights’—habeas cogitationem may also subsidiarily protect these rights (e.g., mental privacy and integrity).

An important question to be elucidated is which neurotechnological interferences should be investigated in a habeas cogitationem proceeding. This is not a trivial matter, since it is often difficult to distinguish whether other types of interferences on the mental and cerebral sphere—particularly psychological influences such as suggestion—violate fundamental rights or instead constitute permissible aspects of social interaction. Similarly, permissible types of neurotechnological interference must be disambiguated from those that erode individual rights. Consequently, and as a starting point, our proposal is that habeas cogitationem be used for those interferences that entail direct, flagrant, potentially irreversible harm, and—as must always be the case with habeas writs—are urgent enough not to be part of an ordinary criminal investigation. As for the potential perpetrators, let us remember that, as we mentioned at the beginning of this piece, both habeas corpus and habeas data, despite being usually employed to address state abuse, can be leveraged as protective mechanisms against abuse by private parties as well. Similarly, habeas cogitationem shall investigate public perpetrators (e.g., governments, courts, police forces, armies, officials) but also private agents such as corporations and attorneys. As we ourselves argue,

[t]he Hobbesian Leviathan is no longer the State only; novel forms of neurotechnological interference in people’s mental lives […] could be developed and applied by new, private leviathans with power comparable […] to that of many states.

It might be held that developing the novel writ of habeas cogitationem implies regulatory redundancy, because other generic procedural instruments exist that could serve the same purpose. An example of this type of generic instrument is the so-called recurso de amparo (in English, ‘appeal of protection’), which exists in several Latin American countries. This writ is conceived for being employed in very diverse scenarios where constitutional rights are violated but more specific procedural mechanisms are unavailable.

In fact, the Emotiv ruling by the Chilean Supreme Court (August 2023), which we explained in the initial section of this piece, was the output of a constitutional appeal similar to amparo, filed in April 2022. Note, however, that the process lasted a total of about seventeen months. Thus, if such a procedural mechanism were used to investigate direct, irreversibly harmful neurotechnological interferences (for instance, a hacking of a DBS device that causes permanent harm), it would not provide effective protection of the rights to cognitive liberty and freedom of thought. Also, in general terms, the more specific a legal instrument is, the more effective it tends to be in protecting rights. For both reasons, the writ of habeas cogitationem becomes a more appropriate instrument for such neurotechnological interference cases than tools such as amparo.

Habeas Cogitationem: Current Regulatory Status and Future Prospects

The need to develop mechanisms for the effective protection of fundamental rights against potential misuse of neurotechnology has been highlighted by two important international organizations, UNESCO being one of them. In its Draft Text of the Recommendation on the Ethics of Neurotechnology (2025), Paragraph 56 stipulates that

[g]overnments   and   societies   should   work   together   to   ensure   those   harmed by neurotechnology have access to justice and effective remedy, and those engaged in wrongdoing are held accountable.

The other international organization, the OAS, specifies the following in its Inter-American Declaration of Principles regarding Neuroscience, Neurotechnologies, and Human Rights (2023):

States shall promote and ensure mechanisms for the effective protection of the rights associated with the development and use of neurotechnologies.

Principle 10

The proposal for a writ of habeas cogitationem clearly responds to this need and, significantly, has recently been specifically recommended in the Council of Europe report “Analysis of the Existing European Human Rights Framework Concerning the Human Rights Issues Raised by Neurotechnologies and Their Applications” (2024):

[A]n emergency judicial remedy called […] habeas cogitationem (from ‘cogitatio,’ meaning thought) could be created to enforce the rights related to the protection of the mental sphere.

Recommendation 9

At the national level, in May 2025, various members of the Chamber of Deputies of Argentina presented a bill so-called Habeas Cogitationem for the Protection of the Forum Internum of Freedom of Thought and Related Neurorights. In this way, Argentina could soon become the first country to introduce this novel habeas writ into its national legislative framework, which already includes habeas corpus and habeas data. By doing so, this nation would establish a comprehensive set of habeas writs that would effectively protect individual self-determination in all its dimensions—physical, informational… and mental.