Brain in a Vat (BIV) Argument From the Perspective of Neuroscience

Author: Elif Dilan Gündüz, Phase 3 Student and member of Hacettepe SIGN 2020-2021, June 2021

What is a BIV?

Imagine evil neuroscientists walking into your home one night and carrying you to their lab, after having applied anesthesia, they removed your brain from your skull and placed it in a liquid, filled with nutrients. In this vat, some cables transmit electrical signals to your brain from a super machine and carry all the signals produced by your brain to this machine. The machine can generate every mental state you can imagine with the electrical signals sent to your brain. So how do you know that your body, your movements, and everything you sense is not produced by such a machine right now? If consciousness arises as a result of electrical activity in the brain, we don’t need the body or an external world, right?

Although that is like an argument from the Matrix, the brain in a vat (BIV) argumentexisted long before it took the form I mentioned above. The first examples of theseskeptical arguments can be seen in the idea of Maya (Illusion) in Hinduism, in thedream that Zhuangzi saw himself as a butterfly, Plato’s cave allegory, or RenéDescartes’ evil devil argument. In fact, the brain in a vat argument is Descartes’argument modernized by Gilbert Harman in 1973.

Counter-arguments to BIV

I will give 6 examples from classical and new counter-arguments, although philosophers have probably made many arguments on the subject.

Classical Counter-Arguments

René Descartes’s Cartesian Approach

René Descartes constructs a thought experiment in which all of our senses are set up by the devil just to deceive us. And he asks, even in such a situation, is it possible that something we are sure of. Descartes’ answer is the famous cogito ergo sum. So even if I am deceived, it cannot change the fact that I am thinking now, and if I do then I must exist. So? Descartes then focuses on his ideas, a tree, or more abstractly a cube, and a lot of other small or big ideas. When he finds the largest of these (this is the idea of “eternal and perfect being”) he says that it cannot be created by an imperfect being, so if I have this idea it must have come from God. He thus concludes that a gracious and infinitely powerful God will not allow Satan to deceive us forever. Of course, there are many missing and perhaps unnecessary points in this solution. For example, How can we know that the devil cannot form the idea of an eternal and perfect being? Or do we really need a god to overcome this problem?

Bertrand Russell’s Approach

Bertrand Russell says “that’s true we might be deceived, but probably we’re not.”. Because, the universe defined by our common sense is simpler, conforming to our daily beliefs, and more systematic, but the skeptical argument is unnecessarily devious, contradicts our daily beliefs, and creates inconsistencies accordingly. This idea does not dispel doubts about our common sense and beliefs, but it does say that because our common sense is systematic and consistent, it would be more logical to take them into account. Of course, there are points in Russell’s idea that we cancriticize, for example, how can we say that the outside world provides the simplest explanation for our senses? After all, isn’t a super machine (or an evil neuroscientist) creating all these senses a much simpler explanation?

George Edward Moore’s Approach

George Edward Moore says that we don’t need a god to criticize the BIV argument. Also, contrary to what Russell said, that there is no need to find the best explanation. According to Moore, we only need to look at our hands to prove the BIV argument is wrong. Moore tells the followings:

  • There is a hand you are looking at.
  • The hand is an external object.
  • Therefore, external objects must be real.

If a skeptic says “How can you tell that you have a hand?” Moore rapidly responds, “Don’t be ridiculous, I don’t need to prove it, we both internally know the existence of the hand.”. What Moore is trying to point out here is actually a reversed version of the BIV argument, because the argument says that if you are in a dream right now, you cannot speak of the existence of a hand you are looking at. Moore translates this into our common sense version: If you are sure that the hand you are looking at exists, then you are not dreaming. Whether Moore’s or skeptical argument wins depends on whether we trust our common sense or take a skeptical attitude as the starting point.

New Counter-Arguments

Hilary Putnam’s Semantic Approach

Hilary Putnam says the skeptical argument is self-destructive. For us to take into account what the skeptics say, they must create a scenario that can be real using meaningful language. Here he asks: “What makes words meaningful?” And answers: “To give a word meaning we don’t have to have a complete explanation of the object it points to. We only need the right kind of connection with the object.” For example, we do not need to know the chemical formula of water to say that we use the word “water” in a meaningful way. Imagine a child, Thales, and a chemistry professor are all saying “I want to drink water”. All can use the word water in a meaningful way because they all have the right kind of communication with the object (water), even though they all have many different opinions about the object. Now that we’ve talked a little bit about Putnam’s Semantic Externalism, we can return to our argument. Putnam says, let’s explore the skeptics from this point of view. If what they’re saying is true, they must be brains in the vat saying they’re a brain in the vat right now. But a brain in a vat cannot reference the brains in the vats correctly, because when they talk about a vat, it’s just the various electrical patterns that the super machine generates. Therefore, there will be no relation between the object corresponding to the definition of the brain in the vat it is talking about an their state. So when they say “I am a brain in a vat,” it means “I’m a simulated brain in a simulated vat.” This shows us that what they’re telling us is wrong, so if our skeptic thinker can say that they’re a brain in the vat, they should not be a brain in avat, instead, someone who can interact with the outside world and aware of the vats. It should be said that this answer is a good response to skeptics who imagined that we are a brain in the vat from birth. But let’s go back to our example, the brain that the evil neuroscientist suddenly stole overnight. The brain has been in proper communication with the objects it interacts with inside the real world before it enters a vat. So what will happen after entering the vat according to Putnam? Will it suddenly stop referencing the outside world? When we think like that, we can see that the boundaries are clouding and Putnam’s argument is not working for this type of situation.

David Chalmers’ Approach

David Chalmers invites us to make a fun distinction. Yes, the skeptics’ argument may be true, that we may be brains in the vats, but it is absurd for skeptics to think of it as “then all our everyday beliefs are wrong”. Because, according to Chalmers, even if we are a brain in a vat, our everyday beliefs remain true. How so? By separating the ultimate truths from the truths that can be generalized in smaller realities. When I say that my hand is touching the screen, I do not need to mention a hand that is accurate in all realities, just for my world – whether simulated by a machine or not – is enough to count it right. If you are not satisfied, I may ask why do we not explain the objects we encounter in our daily life with pure physics, or string theory, for example. Why do we continue to use objects of a smaller and artificial reality when there is a broader reality in which everything can be represented as energy or vibrating strings? This implies that the BIV argument cannot be considered as a threat to our actions and objects in our minds.

Timothy Williamson’s Defense Approach

This approach attempts to address the causes of the endless suspicion of skeptics and to show its meaninglessness. Williamson says that skepticism is a good thing taken too far. He mentions that our critical thinking skills are similar to our cognitive immune system, but exaggerated skepticism is like an autoimmune disease. And he counts the BIV argument in this autoimmune-type skepticism.

What can neuroscience tell us about BIVs?

The signals produced by the relation of the receptor cells that are scattered in our body with the external world and the various chemical signals that are transmitted to neurons from our body are converted into electrochemical information and activates a series of patterns in the specific parts of our brain hidden in our skull. That’s a very brief summary of the knowledge we have (for now) about how our experiences are formed. Doesn’t the “brain in the skull” imagery reminds us of the brain in a vat argument? Despite the similarities, neuroscience has several opinions that the BIV argument is not possible, at least with the brain that we are researching. In this section, I will mention a few of these thoughts.

Embodied Consciousness

Diego Cosmelli and Evan Thompson begin by accepting the BIV argument in an article they wrote and question how the evil scientist can achieve it. According to the argument, the neuroscientists separated the brain from the skull and placed it in a reservoir of fluid containing food. Then they connected the brain to a super machine with a fairly large number of wires that could stimulate it electrically and achieved their evil desires. But is this as easy as mentioned? Difficult problems await this scientist when the brain starts its normal activity. For example, a more actively working area of the brain should have access to more of the nutrients and oxygen in the fluid, perhaps the scientist should consider this problem before directly removing the brain from the circulatory system. Normally, the vessels that nourish the brain expand and contract thanks to local metabolites, providing order in terms of the amount of oxygen and nutrients taken between the active and less active regions of the brain. It can also perform very useful tasks in clearing waste materials that occur in areas of the brain that hardly reach this liquid-filled vat. The accumulation of these metabolites will make it a great challenge to perform the normal functions of the brain contrary to what our evil scientist predicted, altering the stress responses of neurons that detect and react not only to electrical signals but also to chemical ones. Maybe we can decide to keep the vessels going to the

brain in our system, well, what will we do for cleaning the fluid in the vessels, re- oxygenating, and nourishing it? We don’t seem very willing to keep the lung, liver, and heart and put energy into them in our system. However, it is possible to say something about why it would be reasonable to do this. The device we designed must perceive and react to metabolites that indicate that the brain needs energy, and by releasing various chemicals which suspend the chemical response of the brain to need of energy, it must ensure that the brain can continue its normal functions. These control mechanisms, which almost all biological pathways have, are called negative feedback systems. The difficulty of creating activities in the
envatted brain which is similar to activities of an embodied brain is showing us perhaps something bigger. The consciousness we have now is a consciousness shaped by our body and the rules it has. To establish a complete simulation of this consciousness, we will need to continue to send a lot of data to the brain, from our microbiota-derived chemicals that go to the nervous system, to the amount of change in the imaginary positions of our muscles when we move them even if we no longer use. A consciousness that can work and experience without processing this information is probably possible, but that consciousness of course will be quite
different from the consciousness we currently have.

Evolution of the Nervous System:

If we think a little bit about why and how the nervous system and the brain evolved, we may realize that it seems rather strange to say that the human species were brains in the vat from the very beginning. The evolutionary ideas currently accepted say that the first cells resembling neurons differed from epithelial tissue. As we know, there are tight junctions between epithelial cells, and for example, the connections called “gap junctions” enable the direct exchange of ions and chemicals between cells. We think that the first neuron-like cells possessed these properties and thus enabled them to contribute to mainly homeostasis, growth, and differentiation with endocrine-like molecules (called neurohormones). When neuron and neuron-like cells form various networks and can be thought of as a system, the nervous system was expert in controlling movement and maintaining
homeostasis. If we realize that our brain is also formed as a part of these basic mechanisms, even if they are incredible and very interesting on their own, it is not difficult to guess that functions such as consciousness and experience will be operated in a way that will serve this basic mechanism. If we are talking about a brain that looks like it was created for such control and uses its features for this purpose, it should also be said that this brain probably did not evolve to wait in a vat.

Neuroplasticity & BIVs

We know that the brain is an extraordinarily plastic organ, that is, its ability to undergo structural and functional changes is highly developed. If we were trapped in a vat, the evil neuroscientist would have had to put a lot of effort into making our brains work like it’s not in a vat anyway. I have touched on some of these efforts under the heading “Embodied Consciousness”. Again, if I think that I am a brain that has been stealed and envatted, for my consciousness to remain the same, the types of data I normally receive from the external world must be provided by the machine
at the rates I normally receive and as I always receive. This is exactly what I was thinking when I read an article written by David Eagleman and Don Vaughn in 2020. Have you ever questioned why we dream, or even more interestingly, why vision is more intense than our other senses in our dreams? Regions of the brain protect their territory with constant activity: if activity slows or stops (for example, due to blindness), the area tends to be taken over by its neighbors. And recently, there have been experiments showing that this can happen in as little as a few hours. Eagleman and Vaughn argue in their article that the underlying circuit of dreams serves to
periodically boost the activity of the visual system during the night and that dreams emerged as a way to protect the visual system’s territory from capture by other senses. When we see the brain as a democratic battlefield where plasticity takes place so intensely and there is a struggle for survival among the senses, you may have noticed that trying to live in a vat with the experience of a body becomes much more difficult than a skeptic might think.

Modern BIVs

Although I talk about BIVs as very difficult systems to achieve, maybe you have noticed that today BIV-like systems are being worked on. I’ve divided today’s BIV- like systems into two. The first is semi-BIVs, which includes VR technologies and Brain-Machine Interfaces (BMI), which can be seen as modernized versions of the old BIV idea. The second is real BIVs, which include Whole Brain Emulation (WBE/digitized brains) that is easy to imagine with transhumanism and many sci-fi dreams.

Virtual Reality (VR) and BIVs

Yes, VR systems do not separate us from our body, the information of light is
transmitted to the brain by being processed in our eyes, or we use our muscles while making various changes in the VR universe, but they have an important feature of BIVs: They offer us a reality that can be a simulation or a different representation of the outside world and this enables the brain to respond as if the knowledge it has acquired is not a simulation. Some systems did this before VR of course, I think the distinguishing feature of VR technologies comes from the naturalness of the responses given, as well as being an important step for human-machine interfaces.

BMI (Brain-Machine Interfaces) & BIVs

In Neuralink’s recent experiments, with the help of artificial intelligence,
communication was established between monkey brains and computers without any other intermediary (simply by detecting patterns of brain activity). It is possible to see such developments as the second property of BIVs, an important step that enables the brain and the machine to interact directly without any other tools.

Whole Brain Emulation (WBE)

If we just ignore the possible big data problem of the digitized and dynamical brain, there are new concepts that digital brains will come up with, and they look really interesting. For example, let’s imagine that we, as a digital brain, are trying to relocate to a human body at any time and protect our right to live as a biological organism as before, or we want to experience reality as a pre-digital brain for a few years. In this case, a representation corresponding to the body will have to be digitalized to interact with the brain and eliminate all the problems I have talked about in the “What can neuroscience tell us about BIVs?” chapter. However, if we
give the right to leave their body completely to patients who cannot use their body, a new way can be made possible in which the regions of the brain that perform body-related processes can gain very different functions with digital plasticity. Also, a digitalized mind can be copied and ran at any time, potentially making a digitized brain immortal. Perhaps since we do not have an evolutionary structure that can cope with immortality, we will have no choice but to rely on the plasticity of our brain on the digital world and decide to get rid of some body-related structures. Although I do not yet know how far off these futuristic ideas are about tomorrow, if it became possible, I’m sure our species will try to adapt to these realities and we will continue to face new and unique problems and solutions just as in the
adventure of building the cities or democracy. Until that day, what the evil neuroscientist has planned, whether they manage to keep a brain alive in a vat, and what they do with the brain that they separated from the body will remain a big secret for us.


  • Diego Cosmelli and Evan Thompson, Embodiment or Envatment?: Reflections on the Bodily Basis of Consciousness, 2010
  • Keith DeRose, How Can We Know that We’re Not Brains in Vats?, 2010
  • Thomas Nagel, What Is It Like to Be a Bat?, 1974
  • David M. Eagleman, Don A. Vaughn, The Defensive Activation theory: dreaming as a mechanism to prevent takeover of the visual cortex, 2020
  • Anders Sandberg and Nick Bostrom, Whole Brain Emulation A Roadmap, 2008
  • William B. Kristan, Jr., Early evolution of neurons, 2016
  • Jeremy E. Niven, Lars Chittka , Evolving understanding of nervous system evolution, 2016

The Golgi – Cajal Conflict

Author: Leen El Khateeb, Phase 2 Student and member of Hacettepe SIGN 2020-2021, March 2021

In 1906, Camillo Golgi and Ramón y Cajal shared the Nobel Prize in Physiology or Medicine “in recognition of their work on the structure of the nervous system”. This was quite an uncommon occasion in the history of the Noble prize, as Golgi and Cajal’s views on the arrangement of the nervous system were contrasting! While Golgi claimed that the nervous system was a continuous single network, defending the reticular theory, Cajal believed in the individuality of the nerve cell, coming up with the neuron doctrine. Golgi and Cajal’s discoveries were so significant that they marked the beginning of neuroscience as a discipline.

Long before that, in 1839, the cell theory was developed by Theodor Schwann and Matth’as Jakob Schleiden, with contributions from Rudolf Virchow. The theory postulated that:

  • All living organisms are composed of one or more cells.
  • Cells are the most basic unit in life.
  • All cells arise from pre-existing cells.

However, due to the complicated structure of nervous tissues, the histological methods at the time were not developed enough to allow scientists to stain and observe brain and spinal cells. Consequently, nervous tissues were not yet proven to obey the rules of the cell theory. The Purkinje cells which were already discovered, looked more like fibers than to what was then referred to as cells.

In 1873, Golgi’s discovery of the la reazione nera (the black reaction), nowadays called the Golgi stain, was considered a milestone in studying the composition of nervous tissues. When a nervous tissue is stained by this stain, only a small percentage of the cells are stained, making it possible to examine nerve cells and their processes

Using this staining method, Golgi studied the structure of the nervous tissue. He claimed that nerve endings do not end freely, but continue with other nerve endings forming a plexus, thus defending the reticular theory.

Then came Cajal whose fascination of Golgi’s stain is evident when he says, “A look was enough. Dumbfounded, I could not take my eyes from the microscope!” and he continues, “What an unexpected sight! Sparse, smooth and thin black filaments or thorny, thick, triangular, stellate, or fusiform black cells could be seen against a perfectly translucent yellow background!”

Cajal immediately began using the stain in his laboratory studies. He modified and improved the stain and finally reached the conclusion that nerves were individual cells that don’t fuse with other cells in the nervous tissue, which is the complete opposite of what Golgi had proposed. Cajal’s discovery was called the “neuron doctrine”.

Golgi continued rejecting the cellular individuality of neurons, even in his Nobel Prize acceptance speech

But whose theory turned out to be the correct one?

Cajal’s. In the 1950s, the validity of his theory was formally proven with the use of the electron microscope. Even then, when the neuron doctrine became widely accepted, Golgi continued to defend the reticular theory.

Both Golgi and Cajal are two of the biggest names in neuroscience. Cajal’s work is considered one of the biggest contributions to understanding the constitution of the brain structure. He is now known as the father of modern neuroscience. Although he opposed Golgi, he had depended on Golgi’s histological method in his observations and studies

1)Glickstein, M. (n.d.). Golgi and Cajal: The neuron doctrine and the 100th anniversary of the
1906 Nobel Prize.
2)Müller-Wille, S. (2010). Cell Theory, Specificity, and Reproduction, 1837–1870 .
3)Juan A.De Carlos, José Borrell. (2007). A historical reflection of the contributions of Cajal and Golgi to the foundations of neuroscience.
4)Larry W. Swanson, Gunnar Grant, Tomas Hökfelt, Edward G. Jones, and John H. Morrison.
(2007). Introduction to A Century of Neuroscience Discovery: Reflecting on the Nobel Prize Awarded to Golgi and Cajal in 1906.
5)Warmflash, D. (2016). Santiago Ramón y Cajal and Camillo Golgi: The Two Fathers of Neuroscience.


Author: Ceren Özceyran, Phase 5 Student and member of Hacettepe SIGN 2020-2021, January 2021

Firstly, we begin with definition of psychopathy. Psychopathy is a mental antisocial disorder in which an individual manifests amoral and antisocial behavior, shows a lack of ability to love or establish meaningful personal relationships like empathy, expresses extreme egocentricity, and demonstrates a failure to learn from experience and other behaviors associated with the condition. It begins in childhood and persisting into adulthood. 1 In this blog post, I have reviewed some articles related with the differences in brain anatomy and the conclusion of this for criminal psychopaths.

Criminal psychopaths’ brains have some differences from the brain of a noncriminal person. Their brain hemispheres are less lateralized than non-criminals. As a consequence of that, the incidence of non-righthandedness (NRH) is higher in criminal than non-criminal populations. NRH is not a pathological situation; however, elevated NRH may be the conclusion of a developmental/central nervous system disorder.Still, NRH should not be used as a marker of criminality. 4

Lombroso who was an Italian criminologist, who lived between the years of 1835 and 1909. He had a general theory regarding differences between the physical traits of criminal and noncriminal people. Lombroso’s thesis suggested that criminals were distinguished from non-criminals by multiple physical anomalies. He was convinced of the ‘born criminal’ theory. In the opinion of being born a criminal; a criminal could be identified by their anatomical configurations. These include a sloping forehead, ears of unusual size, asymmetry of the face, excessive length of arms, asymmetry of the cranium…5

Current research shows that some structural anomalies associated with the brains of some criminal offenders can be provable with imaging tests. Criminal psychopaths’ brains have atypical structural asymmetries, with reduced right hemisphere grey and white matter volumes, and abnormal interhemispheric connectivity. Functional asymmetries are also atypical, with criminal psychopaths showing a less lateralized cortical response than non-criminals across verbal, visuo-spatial and emotional tasks.2 According to the definition of psychopathy, this structural and functional variation could be associated with antisocial behaviors and a lack of empathy. 

In the ‘criminal brain’, right superior temporal gyrus that plays a crucial role in both empathy and theory of mind may remain under the sway of a pathological condition. Diffusion tensor magnetic resonance imaging (DT-MRI) tractography shows reduced white matter in the right uncinate fasciculus of criminal psychopaths, suggesting abnormal connections in the frontal-limbic networks. Poorer structural integrity was associated with higher levels of antisocial behavior.1 In 1966, Charles Withman had headaches and knew there was something wrong in his brain.  On August 1, he killed his wife, mother and 14 bystanders and shot 43 people unexpectedly. He was named as the ‘Texas Tower Sniper’. At his autopsy, a pecan or walnut-sized glioblastoma multiform tumor was seen in the right temporal lobe. Location of tumor was associated with processing memories, making decisions and controlling emotions.6

Yang, Raine, Colletti, Toga and Narr also found reduced grey matter thickness in the right frontal lobe of a psychopath compared to the brains of non-psychopathic controls. In 1991, Herbert Weinstein, a 65-year-old with no prior history of violence, strangled his wife after an argument, and then threw her body from a window to make her death appear like a suicide. On a structural MRI scan, he was found to have a large cyst in the left frontal lobe, with associated hypometabolism in the cortex adjacent to the cyst on FDG-PET. 7

Tendency to crime can be related with anatomical structure of brain and also synaptic transmissions, neurotransmitters. For more details, you can investigate the references. Thank you!


  1. Henry R. Hermann, Chapter 9 – Alternate Human Behavior, Editor(s): Henry R. Hermann, Dominance and Aggression in Humans and Other Animals, Academic Press, 2017, Pages 139-157, ISBN 9780128053720,
  2. Priscilla Savopoulos , Annukka K Lindell , Born criminal? Differences in structural, functional and behavioural lateralization between criminals and noncriminals, a Department of Psychology and Counselling, School of Psychology and Public Health , La Trobe University , Melbourne , Australia. PMID: 29447065 DOI: 10.1080/1357650X.2018.1432631
  3. Lee Ellis, Chapter 17 Left- and Mixed-Handedness and Criminality: Explanations for a Probable Relationship, Editor(s): Stanley Coren, Advances in Psychology, North-Holland, Volume 67, 1990, Pages 485-507, ISSN 0166-4115, ISBN 9780444884381
  4. Anthony F. Bogaert, Handedness, criminality, and sexual offending, Neuropsychologia, Volume 39, Issue 5, 2001, Pages 465-469, ISSN 0028-3932
  6. Matthew Mcdaniel, THE TOWER SHOOTINGS: Autopsy revealed tumor, but questions linger, Standard-Times, july 2016
  7. R. Ryan Darby, Neuroimaging Abnormalities in Neurological Patients with Criminal Behavior, # Springer Science+Business Media, LLC, part of Springer Nature 2018