A Legal and Ethical Perspective on Human Consciousness and Human Brain Organoids

Since Professor Shinya Yamanaka’s discovery of reprogramming mature human cells into human induced pluripotent stem cells (“iPSCs”) for which he received the Nobel Prize in 2012, human iPSCs have revolutionized the field of medical research.[1]  iPSCs can produce any cell type in the body and can be used to create organoids consisting of self-organizing 3D cells that mimic organ-like features in vitro. Neuroscience is one of the most challenging fields in medical research due to the inaccessibility of brain tissue, however, human brain organoids (“HBOs”), have brought new optimism to neuroscience research. 

HBOs are stem cell-derived 3D brain cells that resemble specific regions of the brain, and allow researchers to study neural circuits and interactions between brain regions in vitro to provide new insights into the central nervous system and neurological diseases.[2] These 3D HBOs are advantageous over 2D brain tissue or neural cells in a petri dish because they more accurately model the functioning of human brain cells.[3] Recently a study has shown that HBOs are even able to produce EEG oscillatory waves similar to those in premature-newborn brains, unlike any other brain surrogate model studied before.[4] HBOs, therefore, have many promising applications, however, as these brain surrogates become more sophisticated and closer to resembling a functioning human brain, they give rise to multiple legal and ethical questions. One of the main legal and ethical questions surrounding HBOs is if they have any capabilities similar to human sentience, such as human consciousness.

The question of what constitutes human consciousness has been debated by philosophers and neuroscientists for several decades. Human consciousness has been described by the philosopher David Chalmers as one of the hardest problems in the science of the mind, and he is of the opinion that “there is nothing that we know more intimately than conscious experience, but there is nothing that is harder to explain”.[5] Although extensive studies have been done by neuroscientists to determine the origin of human consciousness, no consensus has been reached in the scientific community on where consciousness originates from.[6] The notion of what constitutes human consciousness is however becoming more relevant in light of our current technological era with technologies such as artificial intelligence, brain-computer interfaces and virtual and augmented reality which threatens our current understanding of human consciousness. As a legal scholar, my attempts to understand and explain human consciousness from a philosophical or neuroscience perspective will be futile, and therefore I will instead allow the law and ethical principles to guide me as I attempt to scrape the top of the surface of the notion of human consciousness, and how it relates to HBOs.

From a legal perspective, legal personhood, for a natural person, is attributed to “every infant member of the species homo sapiens who is born alive at any stage of development” in 1 USC §8.[7] And, a natural person’s legal personhood ends when a person has been declared legally dead which occurs when “an individual has sustained…irreversible cessation of all functions of the entire brain, including the brain stem”.[8] If we accept that the human brain is the source of human consciousness, which is the current neuroscientific understanding[9], then it can be argued that human consciousness is linked to legal personhood in the sense that if the entire brain permanently loses its function, then there is no source of consciousness. If this line of reasoning is followed, then human consciousness cannot be attributed to anything that has not been born alive (i.e. the start of legal personhood), and HBOs, which is not considered to be an infant that has been born alive from a womb, does not have legal personhood and therefore does not have human consciousness. 

Some scholars have however argued that due to the fact that HBOs have neural activity, they cannot be considered to be legally dead in terms of the legal definition of death and should therefore be considered to have legal personhood.[10]  This argument has been criticized on the basis that the neural activity that HBOs illustrate is not the same as the neural activity that integrates the human body as a whole, and therefore at this moment, it is widely accepted that HBOs does not have legal personhood.[11]  

From an ethical perspective, it has been argued that if one aspect of human consciousness is defined as having the ability to experience subjective phenomena, such as pain, then HBOs, which have neural activity similar to those in premature-newborn brains, may have some degree of human consciousness.[12] If HBOs indeed have some degree of human consciousness, it would be unethical not to attribute a moral status, with possible accompanying rights, to them.[13] Although it seems unlikely that HBOs will be able to have the same level of consciousness as humans without the same external sensory input that humans receive from their physical bodies, the possibility might be there that HBOs will exhibit some features of human consciousness, especially if their ultimate goal is to more accurately resemble the human brain in vitro. 

Currently, we do not have any parameters or guidance on how to determine with certainty if HBOs are indeed able to have any degree of human consciousness. Due to this uncertainty, it has been argued that the precautionary ethical principle should be applied to HBOs, and guidelines and regulations on research limitations with HBOs should be implemented to prevent unethical research.[14] As with most ethical questions, there is also an opposing view that since there is no sufficient certain evidence that a fetus has some sense of sentience before 20 weeks of gestational age, this limit, at least, should also be applied to HBOs, and research on HBOs should be allowed until they resemble the same neural activity of the brain of a 20 weeks old fetus.[15] 

In my opinion, even if HBOs are not considered to have legal personhood and therefore don’t have any rights in the legal system, the question of their human consciousness from an ethical perspective cannot go unnoticed. Until we have a method of determining when and where exactly human consciousness arises, which presupposes we have consensus on what constitutes human consciousness we cannot say with certainty that HBOs either have or don’t have any level of human consciousness. 

The science in the field of HBOs will unwittingly keep on making big leaps of progress, for example, researchers are now aiming to create “organoid intelligence” by integrating artificial intelligence into brain organoids.[16] In light of the uncertainty surrounding the question on if HBOs indeed have any degree of human consciousness, from a public perspective it is important to remember that how we address the question of human consciousness relating to HBOs will have an impact on the public’s acceptance of new treatments and inventions that are created from HBOs. It is therefore essential that, sooner, rather than later philosophers, neuroscientists and legal experts reach consensus on where, if any, the boundaries should be set for experiments with HBOs, in order to prevent questions surrounding human consciousness of HBOs from hindering research and innovations in the field of neuroscience.

[1] The Nobel Prize in Physiology or Medicine 2012, NobelPrize.org, https://www.nobelprize.org/prizes/medicine/2012/press-release/ (last visited Apr 22, 2023).

[2] Neal D. Amin & Sergiu P. Paşca, Building Models of Brain Disorders with Three-Dimensional Organoids, 100 Neuron 389 (2018).

[3] Nita A. Farahany et al., The ethics of experimenting with human brain tissue, 556 Nature 429 (2018)

[4] Cleber A. Trujillo et al., Complex Oscillatory Waves Emerging from Cortical Organoids Model Early Human Brain Network Development, 25 Cell Stem Cell 558 (2019); Takuya Niikawa et al., Human Brain Organoids and Consciousness, 15 Neuroethics 5 (2022).

[5] Facing Up to the Problem of Consciousness, https://consc.net/papers/facing.html (last visited Apr 23, 2023).

[6] Wayne Wu, The Neuroscience of Consciousness, in The Stanford Encyclopedia of Philosophy (Edward N. Zalta ed., Winter 2018 ed. 2018), https://plato.stanford.edu/archives/win2018/entries/consciousness-neuroscience/ (last visited Apr 23, 2023).

[7] United States: Congress: House of Representatives: Office of the Law Revision Counsel, 1 U.S. Code § 8, (2011).

[8] National Conference of Commissioners on Uniform State Laws, Uniform Determination of Death Act, (1981), https://www.uniformlaws.org/viewdocument/final-act-49?CommunityKey=155faf5d-03c2-4027-99ba-ee4c99019d6c&tab=librarydocuments (last visited Apr 4, 2023).

[9] David B. Fischer et al., A human brain network derived from coma-causing brainstem lesions, 87 Neurology 2427 (2016).

[10] Andrea Lavazza & Federico Gustavo Pizzetti, Human cerebral organoids as a new legal and ethical challenge†, 7 J Law Biosci lsaa005 (2020).

[11] Masanori Kataoka, Tsung-Ling Lee & Tsutomu Sawai, The legal personhood of human brain organoids, 10 J Law Biosci lsad007 (2023).

[12] Jacob Jeziorski et al., Brain organoids, consciousness, ethics and moral status, 144 Semin Cell Dev Biol 97 (2023).

[13] Andrea Lavazza, Human cerebral organoids and consciousness: a double-edged sword, 38 Monash Bioeth Rev 105 (2020).

[14] Jonathan Birch & Heather Browning, Neural Organoids and the Precautionary Principle, 21 The American Journal of Bioethics 56 (2021).

[15] Julian J. Koplin & Julian Savulescu, Moral Limits of Brain Organoid Research, 47 Journal of Law, Medicine & Ethics 760 (2019).

[16] Jamie Derita & JH Bloomberg School of Public Health, Organoid Intelligence, Johns Hopkins Bloomberg School of Public Health, http://caat.jhsph.edu/programs/oi/ (last visited Apr 29, 2023).