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Is a brain a human being?


Published: 12 December 2019 (GMT+10)

Is the mind all that matters?


What makes us human? What is the smallest set of organs necessary to make a human? How far can you reduce the body until what is left cannot be considered alive? What about the soul? Some previous cultures considered the heart or the bowels to be the very core of humanness. In the 17th century, the French philosopher René Descartes made the famous statement “Dubito, cogito ergo sum”, meaning “I doubt, therefore I think, therefore I am”.1 What Descartes meant by this statement, is even if we doubt everything that our senses are telling us, we can still sense our own mind at work. In other words, our mind can think about its own self.

The brain is the physical seat of cognition and all mental activities. All sensation ends up in the brain, where it is organized, interpreted, and responded to. According to some clinical definitions, a person is pronounced dead if his brain ceases to function, besides the cessation of circulation and respiration. The body cannot function if the brain does not function at a basic level. Surgeons have even been able to perform head transplants on monkeys and are planning to perform them on human subjects.2 This shows how important the brain is to the rest of the body. Therefore, some people say that the mind is the seat of our humanness.

Organoid experiments

Muotri Lab, UCSDbrain-organoids
Brain organoids grown in the lab.

This being said, would it be possible to isolate the mind from the rest of the body and artificially keep it alive? Why even ask this question?

Researchers who wish to study the development of the nervous system and certain neurological diseases cannot simply run life-threatening tests on people’s brains while they are alive. That is a clear ethical violation.

That is why in recent years, scientists have been culturing brain organoids for the opportunity to model early neural development, and study drug effects on the mind, as well as mental illnesses, such as autism, microcephaly, and schizophrenia.3 Researchers also want to study brain organoids so they can compare them with those of ape species in evolutionary studies.

An organoid is a mass of tissue which comes from an organ of a person’s body, such as liver cells, which researchers use as a miniature model to study biological processes happening in the real tissue or organ. Hence the term organoid, denoting a smaller version of the organ. Organoid studies are preferable to studies done on entire embryos, since only a single organ is being modeled. This way no ethical issues arise concerning the use of human subjects in medical studies.

Brain organoids come from human body cells, such as skin or blood cells, which are re-programmed into so-called ‘pluripotent’ stem cells. These are cells, which have general cellular characteristics. They do not fulfill any specialized function in the body, such as muscles cells or bone cells, which are involved in movement or body structure. Some of these pluripotent stem cells can then differentiate into brain cells and can even self-organize into three-dimensional structures resembling a human brain.4

Brain organoids are about one-millionth the size of normal brains (see figure 1). Their disadvantage is that they do not contain all the types of cells in the brain of a mature human being. Researchers can use them to model diseases only imperfectly. Furthermore, the test tube environment that they are grown in isn’t the same as the uterus, where a baby normally develops, which is a very important factor during human development. This is because the uterus is a more suitable environment than a Petri dish for human development. Because brain organoids lack blood vessels and other cell types which are necessary for further growth, brain organoids generally rot after a while.

Cells in brain organoids even separate into different cell layers, which is reflective of finer tissue structure. Brain organoids also show differences in structure when grown from normal brain cells and between those which were grown from patients with autism spectrum disorder (ASD).5 However, even though the brain organoids develop separate regions, these regions are not exactly the same as in a real, normal brain, because they cannot sense the axis of its non-existent body.

Recently, Dr Alysson Muotri, a professor at the School of Medicine at the University of California in San Diego has been able to detect brain waves emanating from brain organoids that he has been studying. These brain waves appeared at two months of development, which is characteristic of very immature human brains. After the brain organoids developed further, their brain waves appeared more regularly and at different frequencies, indicating that the brain organoids’ nervous system had become more developed.6 This gave rise to concerns by these researchers as to how far they can go with developing brain organoids, which, in their view, might be showing the first signs of consciousness.

Is it right to grow brains in the lab?

If the mind is the seat of our humanness and we are now capable of growing brains in Petri dishes, this raises a whole slew of ethical questions. If brain organoids can produce brain waves, what exactly is it sensing? If the organoid reacts to stumuli, is it just a physical response, or does it consciously feel pain? Does the brain organoid have a soul? Is it a person? If so, does it have the same rights as everyone else? What do we do with brain organoids grown in the lab which are not needed anymore? Since organoids are harvested from living individuals, this would mean that the organoids are clones of human body parts. But since, unlike many other body parts, we cannot live without our brains, this might lead some to wonder whether a laboratory brain is not merely a body part, but an individual person. This might also raise the question of whether clones are fully human?

On 21 Oct 2019, researchers from the Green Neuroscience Laboratory in San Diego urgently called for a definition of what point a brain tissue can be considered sentient (conscious).7 This is important, because after a certain stage, some researchers argue that brain organoids might be able to sense pain. Of course, this is debatable, but the question is worth considering, so that researchers do not induce unnecessary suffering, even if it is ‘just’ a mass of tissue.

Researchers have no way of determining whether brain organoids are truly conscious. The best that they can do is to apply tests that are used on brain-injured non-communicating patients, but these tests are very limited.8 The problem is made all the more difficult since pain is subjective—we can’t get inside the brain organoid to determine how much it could be suffering in the case that it turns out the entity is more than a mass of tissue.

The fact that researchers have been growing brain tissue in the lab for some years now without seriously asking these questions is an indication of the lessened value of human life nowadays. These ethical questions should have been the first thing to resolve before such experiments were even allowed. Think about it—would you be happy if researchers thoughtlessly conducted tests involving highly radioactive material near your town without your consent?

The way the world views it, experiments on possibly conscious brain organoids might be worth it, if the risk to benefit ratio is low enough. In other words, it’s worth sacrificing even conscious brain organoids in order to help cure mental disorders. One secular author writes “On the one hand, we may have the interests of a patient with Alzheimer’s disease who is likely to fall into total oblivion, and on the other hand the suffering of an entity comparable to a very simple lifeform that we would usually be willing to sacrifice in the face of the interests of a human being.”8

This brand of humanistic ethics is called hedonistic consequentialism, which decides whether a given action or policy (such as growing brain organoids) is ethical based on its ‘intensity, duration, certainty, availability, purity, fecundity (abundancy), and extent (number of affected people).’9 Its goal is to maximize well-being and minimize pain, hence the name hedonistic. However, researchers cannot accurately foretell future consequences of such tests on brain organoids. For example, when in vitro fertilization techniques were first made available, it was not yet known that these techniques cause a small, yet significant rise in the number of birth defects.10 Moreover, protocols for even larger, more developed brain organoids have not yet been developed. This makes forecasting the effects of brain organoid research even more uncertain.

In comparison, many secular researchers conducting experiments on embryos draw a boundary at 14 days, because this is the latest time point when a mother can have twins. In other words, at 14 days the human embryo is still not yet developed enough so that it can fall apart without any consequences to both twins which are a result of the split. At this stage the embryos have not yet developed a neural tube,11 meaning that the embryo at this early stage does not feel pain. We point this out not to endorse the drawing of the boundary lines here, but to say that this is at least preferable to a situation where there are no boundary lines, as is the case currently with brain organoid research. A human embryo should have the right to life in virtue of being a whole, distinct, living human, regardless of its stage of development or ability to feel pain. Twinning can be understood as a type of natural cloning, so does not demonstrate that the earlier embryo is a non-individual.

Experiments have been conducted by scientists on other kinds of organoid tissues for years. For example, cancer researchers have been studying liver cancer using organoid cultures, which are clumps of cancer cells in a Petri dish. Some kinds of cancer cells have been kept alive in test tubes for years, for example the HeLa cells from a cancer patient called Henrietta Lacks, who died of cervical cancer in 1951. These types of tests are different from brain organoids, since they don’t involve the brain, an organ which we cannot live without, and through which we control the rest of our bodies. Our skin sheds cells all the time as the skin grows. We can lose blood from an open wound. An amputee can lose a limb, but the loss of all of these other organs do not make us less human.

In the case of brain organoids, it might not yet be a problem if the tissues are grown until a certain stage. A single nerve cell does not yet constitute an entire brain. Researchers study individual cells in the lab all the time, without any ethical concerns. Single brain cells in isolation show biological activity just like any other kind of cell. There’s also the question as to whether brain organoids really can feel pain, if they don’t have any pain receptors relaying signals to the brain. With brain organoids we don’t have the exact same problem as with abortion, where life must be protected at all costs starting from the fertilized egg, since life starts at conception.

Furthermore, even if we could grow an entire human brain in the lab that was fully functional, physically speaking, this might pose no ethical difficulties if the isolated brain turns out to be merely a body part rather than a whole individual human being. An artificially grown brain, unlike the human embryo (however it was conceived), would not have the capacity to self-direct its own development (in the proper environment) to grow a complete human body. Thus, it would arguably not have a soul, not be conscious, and not truly feel pain or feel anything at all. But these are the issues that ethicists must address before the research recklessly marches onward.

Nevertheless, ethical concerns regarding brain organoids still arise. What should we do with these organoids after we have used them? Would it be permissible to destroy them? If they are conscious, and if they produce cell layers much like normal brains, then it might not. Should we store them in refrigerators at extremely low temperatures in a state of suspended animation? This is what they do with surplus embryos which have been created in a Petri dish for infertile couples. But is this the right thing to do with something you could consider to be a human entity? Would you assent to being put unconscious and being stored in a refrigerator for decades? On top of this, would you also assent to being denuded of your entire body and stored in a jar full of culture medium?

Maybe not.


The study of brain organoids has very complex and far-reaching philosophical and ethical consequences. We stand to gain a lot of medical knowledge using organoids in order to alleviate human suffering. For example, one potential application of organoid research is growing personal organs from an ailing patient to run experiments on their duplicated organ. This way we can find an accurate, personalized cure for patients with minimal pain and intervention.12

In the meantime, we should not proceed with research until we know whether the subject of our study is a human person. If these brain organoids are mere tissues—with no soul, no awareness, no individual personhood, then the above concerns are alleviated. But if we think they could be undeveloped yet complete individuals made in God’s image, the picture changes dramatically.

The most important issue at stake here is the value of human life. The world considers human life as possible subjects of medical studies without consent. Fetuses are labelled as a more primitive stage of evolutionary development (often based on Haeckel’s fraudulent embryonic recapitulation theory), meaning that it is permissible to abort them. In a similar vein, brain organoids are considered more simple life forms with a diminished level of consciousness. According to secular thought, it does not matter whether brain organoids are full-fledged members of the human community. Given their level of physical development, they can be disposed of just like aborted embryos.

God’s Word presents a different picture of human life. Psalm 139:13–14 says “For you formed my inward parts; you knitted me together in my mother’s womb. I praise you, for I am fearfully and wonderfully made. Wonderful are your works; my soul knows it very well.” An embryo is fully human, even from a single-cell stage. That is the fundamental question we must ask of a brain organoid as well. If it gains consciousness, then we would have to consider it human too. We may neither abort the fertilized egg cell nor conduct any kind of experiments on embryos, nor may we destroy the conscious brain organoid. Whereas we must allow the fertilized egg cell to live and develop into a mature human being, we must also do no harm to any other human life if it is found to be such.

References and notes

  1. Descartes, R., Discourse on the Method, Amsterdam, 1656. Return to text.
  2. Suskin, Z.D. and Giordano, J.J., Body-to-head transplant; a ’caputal’ crime? Examining the corpus of ethical and legal issues. Philos Ethics Humanit Med. 13(1):10, 2018. Return to text.
  3. Di Lullo E. and Kriegstein, A.R., The use of brain organoids to investigate neural development and disease, Nat. Rev. Neurosci. 18(10):573–584, 2017. Return to text.
  4. Kelava, I. and Lancaster, M.A., Dishing out mini-brains: Current progress and future prospects in brain organoid research, Developmental biology 420(2):199–209, 2016. Return to text.
  5. Mariani J. et al., FOXG1-Dependent dysregulation of GABA/glutamate neuron differentiation in autism spectrum disorders, Cell 162:375–390, 2015. Return to text.
  6. Stetka, B., Lab-grown “Mini Brains” can now mimic the neural activity of a preterm infant, Scientific American, scientificamerican.com, 29 Aug 2019. Return to text.
  7. Martin, S., Blob-like brains created in lab could have ‘thoughts’ and are ‘suffering’, scientists warn, express.co.uk, 22 Oct 2019. Return to text.
  8. Lavazza A. and Massimini M., Cerebral organoids: ethical issues and consciousness assessment, J. Med. Ethics 44(9):606–610, 2018. Return to text.
  9. Holmes, Arthur F., Ethics: Approaching Moral Decisions, Second Edition, IVP Academic, Downers Grove, IL, 2007, p. 45. Return to text.
  10. Davis, John J., Evangelical Ethics, Third Edn, Presbyterian and Reformed Publishing, Phillipsburg, NJ, 2004. Return to text.
  11. The neural tube is the first stage of development of the nervous system. Return to text.
  12. Clevers H., Modeling development and disease with organoids, Cell 165(7):1586–1597, 2016. Return to text.

Helpful Resources

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Readers’ comments

Jordan C.
I always enjoy your articles, thank you Dr. Matthew! This is a very interesting article! I am under the impression that the human brain, as with most internal organs have little or no pain receptors, hence are unable to feel pain, though I am ignorant as to how relevant these cell types/structures are to brain tissue in an living organism as a functioning whole. I wouldn’t assume pain would be “the” determining factor for morality? I understand that it would be immoral to withhold pain medication to a “patient” in suffering but the application of moral standards regarding pain becomes situational. We believe God has good reason to allow pain. Pain is a critical indicator to warn us of external dangers, say a stove top. An unconscious person may feel no pain to euthanasia, or a conscious person may feel no pain to a lethal sedative, but we all agree that neither option is moral by Biblical standards. It may be painful to have an operation, but without surgery one would likely die. I’d assume that consciousness should not be a deal sealer either, most of us have been either knocked out or sedated for surgery, completely oblivious to the world or our own existence for a matter of hours. It would be immoral for someone to murder us just because we weren’t aware of it. We know that once embryological development begins at conception, the life of a new person begins, as reinforced by Psalm 139:13–14. From a dualist perspective, the soul has intentionality, brain cells do not, though sharing an intricate relationship with the mind, brain cells collectively or individually are not souls and so does not constitute as a person physically or spiritually. Is this right?
God bless CMI! :)
Matthew Cserhati
Hello Jordan,
Thanks for your comments. As to whether brain cells individually or collectively have souls or not is a very speculative question. First off, we can say that at conception the fertilized egg becomes human. However, we have to differentiate between this and a bunch of skin (or brain) cells which have been removed from the body. These do not constitute a human being, so therefore they would not then have a soul.
Dorcas S.
There are very real ethical issues in the world, clear cut ones that need no guessing games or muddled thinking: babies are being aborted, human body parts being used from them in research, there is forced organ harvesting and other such evils occurring. Diluting down the message of "Thou shalt not kill" with a conversation about neuronal blobs is inappropriate for the standard that CMI has set, and which I have greatly utilized and enjoyed. With this article, I am disappointed. When everything is added together, real and maybes, then the true evil of mankind killing mankind against God's wishes is so diluted that it becomes an opinion game, and almost has an Alinsky type technique to it. Growing organs such as liver and others from a person's own cells is one way of allowing people to have transplants and not reject them. Studying how cells react in a petri dish allows us to develop medications and treatments for people. When done in harmony with God's law (i.e., using skin cells or blood cells from donators, and not from embryos or aborted babies) then it may have the blessing of God and produce a good work. When done in violation of God's law, then clearly it can be used for evil, as can anything that God has created, that sin has defiled. Talking about this as if maybe the brain organoid is a human being is a blight to your site, where most deal with facts and reality. Interesting subject and should be kept track of, agreed, but treating it as if it falls in par with human beings was a mistake. The result is that it degrades the article. CMI usually produces such great work. Let us run the race together, focus on the prize, and not get side tracked, however fascinating it might be to speculate. With love, your sister in Christ.
Philip G.
It's a difficult and complex question. However, I can accept that an embryo is fully human at conception because it arises from the union of the male and female seeds. A brain organoid is simply tissue grown from the base brain cell. Brain waves may simply be a function of brain cells without being evidence of consciousness. My scriptual understanding of consciousness is an attribute of the soul. The soul and body are so intricately and mysteriously knit together, that it's beyond our understanding. Growing organoids, as I understand, could not produce a soul.
Antonio F.
I don't think Christians should confuse the evolutionary claim for life with God's scriptural definition for life. According to evolutionists they consider anything that holds to the HOMR principle as life, H - homeostasis, O - organisation, M - metabolism, R - replication (and sometimes E - evolution, which I don't know how they get to since nothing in biology fits E). This includes things like plants, bacterium, insects, etc, or organoids in this case. According to scripture we know that animals are nephesh (subjective - unaccountable) and that we are nephesh chayyah (objective like the angels - accountable). Other scripture tells us that God knitted us together in the womb so only God's mechanisms of procreation are life bringing. Just because the organoids show wave length responses that doesn't mean they're life. Experiments on plants show them responding to a cut by sending repair signals even before being cut, similar to the way our nerve signals work even before we touch something or are even consciously aware of what's happening. These mechanisms are likely just electromagnetic signals due to concentration changes occurring near the surface showing us that our bodies are only the physical part of who we are and that us being created in the image of God is in relation to our eternal souls. It also shows Gods omniscience, omnipotence, and omni-benevolence in knowing that these mechanisms are needed to ensure that everything works for the good of His creation.
Joshua W.
I found this incredibly disturbing, especially the aspect that brain organoids have brainwaves. The whole idea of creating brain organoids is utterly horrifying. I think this raises a serious issue. If we consider that a person is human from the moment of conception with a soul (despite having not yet developed a brain), then there cannot be a level of complexity at which a brain organoid "becomes" human. How can we be taking the chance that reprogramming cells to create brain organoids does not effectively create an immature, horribly mutilated human? We cannot answer the spiritual questions here and the ethical implications are terrifying.
Joseph B.
If we truly did have a soul, what would you expect to see in this situation? Is the brain simply the computer at which the person (soul) uses to interact with the world? Would this mean a soul would be assigned to each brain and there for each developing brain? Not sure we can find out that particular question. How would our view differentiate from a naturalistic view in this circumstance?
Matthew Cserhati
Hello Joseph,
Thanks for your comment. The embryo is not yet a fully formed human being, but we believe that it still has a soul. Thus, it might be possible that similarly, at a certain stage a brain organoid might also have a soul. We don't know for sure, because experiments haven't proceeded to that point yet. The atheist view states that humans are mere monads, and that a souls is an intangible manifestation of the workings of the brain. But atheism can in no way explain self-consciousness, emotions, abstract thought, religious experience, etc.
Thomas C.
Weren't we told that the brain has no pain sensors? If so, how do they expect to detect it is sensing pain? Also without a mouth lungs etc, speech organs, how could they sense it is communicating?
Scripture says man became a living being when God breathed life into him. Isn't that the input of a spirit, which is non-material, correct? So then if so, no artificial collection of 'brain' cells really cannot be sentient.
Matthew Cserhati
As of yet neuroscience has not discovered whether the brain itself has pain receptors. It is an undecided question as to whether the brain receives a soul or not. The brain is different from all other organs in that it is the seat of consciousness. The brain controls all other organs. The brain itself can exist without any other organs. A person becomes human at conception, which is obviously different than transforming a skin cell into brain tissue, so that indeed is a more open-ended question as to what point a brain organoid can possibly become human (receiving a soul as well).
Sam E.
The brain does not have pain receptors, it shouldn't be in physical pain. I'm not a neurologist though.
Matthew Cserhati
Hello Sam,
Thanks for your comment. In my article I mention that some researchers pose the question as to whether the brain can feel pain (because we do not know everything about the brain). This is speculative, that is why I qualify these statements: "There’s also the question as to whether brain organoids really can feel pain, if they don’t have any pain receptors relaying signals to the brain."
Kevin R P.
Thanks for the article. We know so little about what happens at conception. It is possible that, at the moment of conception, if a woman is going to bear triplets, that three complete and eternal souls are created, even though there is only one cell. These souls may live in and around their mother until "deliverance". If a pregnancy terminates early (perhaps though the use of Plan-B) the souls may follow the course of all other eternal souls. (Some believe in an age of accountability. I am not sure.) There was a time when humans could not observe or measure molecules. That did not mean that molecules did not exist; only that humans could not observe them. Currently humans are not able to observe angels, demons, or souls. This is not evidence that they do not exist only that humans are not currently capable of observing them. Thanks again.
This article definitely makes one think. We cannot predict what future researchers will be doing, but at least we can keep up on some of it thanks to articles like this one. I was a little bothered by the use of the words “brain” and “mind.” You used them interchangeably several times, which I think is misleading. The brain is biological; the mind is not. I know that neuroscience says, at least sometimes, that the brain is the organ that makes possible the mind, but I do not believe it is. There should be little doubt that in the future artificial/electronic “brains” will be able to send signals to do jobs similar to what our brains do now. Already this is happening is some experiments such as in hearing and sight. I was hoping that your article would have said more about how much of a person’s body can be missing and there still be a person. Such studies may seem silly to some, but Creation.Com has shown that Christians need to be prepared for what comes. I appreciate this article and others like it.
Filipe J.
How can we relate this with the soul? If the organoids have thoughts, these do not show that the soul don’t exist and all is needed is the brain? God Bless you.
Michael B.
I wonder if these are capable of (or maybe already are) interfacing with the spiritual world (demonic?)
When Jesus cast the demons from the man and sent them to the swine the madness went from the man to the swine.
We know nothing of how any of that works; of how the man became possessed and how at a word from Jesus these things left one abode to be in another.
Just some uneasy musings that also need spoken of.
Your Brother in Christ,
Robert P.
A fertilized embryo in utero has the full potential of a human being. A "brain" organoid in a dish however, does not. It is therefore not human. To think because their is differentiation in its internal structure, it is therefore now sentient, tells me that someone has been watching way too many Star Trek Voyager episodes (also known as ethics novellas). To use the prefix "brain" for a blob of neural tissue indicates either massive hubris, or an utter ignorance of the staggering complexity of the mamalian brain, the human brain being in a class apart. I should be more concerned about the real and obvious suffering caused to higher mammals (Nephesh chayyah) for the purposes of medical research. This is a real ethical dilema, that is not consistent with the originally "very good" created order. As Christians, we are part of the restoration crew, not the wrecking crew. The mystery of life and more so human life, of being created in Gods image, along with the human mind is truly profound. Materialistic science cannot examine a soul and/or a spirit in a petri dish. It cannot be weighed, touched or smelt. It is immaterial. What does that mean? The Bible tells us that their is more to our existence than the material world around us. Otherwise what does it mean when the Bible says that God is Spirit, and those who worship him must worship in Spirit and truth" ? Is that just poetry or is that reality? As wise Solomon wrote: As you do not know how the spirit comes to the bones in the womb of a woman with child, so you do not know the work of God who makes everything. (Ecclesiastes 11:5 RSV)I hardly think a blob of partially organized neurons in a dish "about one-millionth the size of normal brains" meets the Biblical definition of Nephesh Chayyah. Gettest thou a grip!
Matthew Cserhati
Hello Robert,
Thank you for your comments. Although, I might want to add that nobody can get into a brain organoid. To claim that it cannot think is subjective. We cannot feel or sense the way such an organoid might possibly do.
Amanda M.
Wait, so do they kill the host to get the brain organoid, or is it done without killing the donor?
Matthew Cserhati
Hello Amanda,
There is no donor, the cells are taken from somatic (body) cells (i.e. skin cells) and undergo chemical treatment to turn them into brain cells. The point is that they don't take brain cells from live donors, that's unethical.

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