Whole brain emulation is the theory that brain scans can be used to simulate the human mind digitally. It is primarily being researched to improve understanding of the brain to treat or cure neurological illnesses and conditions. However, the concept of whole brain emulation raises ethical and philosophical questions about what it means to be human and the future of humanity. This paper explores different schools of thought on the ideas of consciousness and how they can be applied to the concept of brain simulation and ethical research practices.
What does it mean to be human? Is it about being organic? All lifeforms on this planet are organic. Maybe it is about a unique biology, such as hands, legs, and skin. However, somebody with a prosthesis is no less human than anyone else. Plenty of people are also born without certain body parts, which does not make them any less human. So, perhaps it is empathy, or a seemingly endless capacity to think and reason. Yet, the human mind is not some mythical, imaginary concept – it is a physical thing. That idea implies that everything that defines what it means to be human is dependent on one thing: the brain. A complicated bundle of synapses and electrical impulses defines the human species, humans as individuals, and the entire human existence.
What if it could be replicated? What if an individual’s brain could be copied to a single-axon level? What does it mean to have a consciousness and sense of self? These questions frame the conversation surrounding the ethics of using technology to simulate the human brain.
Whole Brain Emulation:
The concept of Whole Brain Emulation (WBE) could convincingly belong to the science fiction genre. The WBE theory proposes that because the human mind is a collection of electrical impulses, it is possible to model them using a computer. Thoughts, feelings, and emotions from a human mind could be simulated with immediate accuracy .
The human mind is incredibly complex, and scientists still do not completely understand it. A common perception is that this lack of understanding prevents active research into simulating the brain and that whole brain emulation is impossible. However, there is a big difference between something that will take a long time to develop and something impossible [2, 3]. Foundational research is currently being conducted on simulating brains on a smaller scale. Researchers Shawn Mikula, Jonas Binding, and Winfried Denk published a paper in 2012 in which they developed a plan to use 3D electron microscopy (EM), a technique for obtaining high-resolution images, to completely map a mouse brain at the single-axon level [2, 3, 4]. Combined with Serial Block Face Scanning, EM would map the brain at a close enough level to unambiguously map all its connections .
The proposed plan would take years; recreating this process on a human brain would take significantly longer. The technology for mapping and simulating an entire human brain is not currently available, but it is possible. This means that whole brain emulation likely is not a question of “if” but “when.” Therefore, it is imperative to discuss the ethics and potential ramifications of the technology before it is developed.
Consciousness and the Self
Whole brain emulation asks researchers to consider what it means to be human. Is humanity dependent on minds or bodies? Answering this question requires analyzing the philosophy of the human mind and what makes a person who they are. The definition of being human often includes a discussion of consciousness and the self, so it is no surprise that philosophers and ethicists have pondered these questions for centuries.
René Descartes, an early 17th-century French philosopher, defines consciousness as acknowledging existence by having thoughts and making reflective ideas about them. Consciousness requires thoughts to be clear to the mind, involving reflection and intentional conscious thought; or as Descartes phrased it, “I think, therefore I am.” What, then, defines thinking? In Descartes’s definition, thinking is an attribute of the mind. The mind is a physical substance and thought occurs naturally as an inseparable part of it .
Later, David Armstrong proposed a different theory of consciousness in his book A Materialist Theory of the Mind in 1968. This theory claims that a high degree of perception is necessary for a being to be conscious. This theory differs from Descartes’ as it does not define thought as a necessary part of the mind. One must be able to perceive the external world and provide introspection into themselves . What, then, is introspection? How can one achieve it?
This is the challenging part of defining consciousness. To delineate an abstract idea, it helps to create an explicit definition. One can claim unconsciousness is to be unaware and unresponsive, but this still does not provide an adequate definition of consciousness itself. One can also explain examples of consciousness, such as Descartes’ reflection of thought or Armstrong’s models of perception, but the examples themselves do not supply a concrete definition. By this logic, a philosophical definition of consciousness remains up for debate. However, neurologically, human consciousness is not quite as abstract. So, if the human brain is believed to be conscious and is then recreated on a computer, this version must also be conscious. The digital mind must be functionally and qualitatively identical to the original model .
A smaller example can be used to demonstrate modeling the brain: modeling a human retina. The retina comprises neurons that feed into a layer of cells that form the optic nerve. A small camera and microprocessors could be used to create an artificial eye, thus creating a simulation of a retina. If the functions of a person’s retina were recorded and the eye were replaced with the previously made camera and this recording, the person would still be able to “see” with the simulated eye. If it is possible to replace an eye, it should be possible to replace human vision completely with a simulation .
This logic can be expanded to the entirety of the human mind. Some argue that external stimuli can be simulated, but inner processing, such as memory and decision-making, cannot be. However, neuroscience makes no distinction between these two modes . Therefore, a completely simulated human brain would be just as conscious as an organic one. It could also operate under Descartes’s idea of consciousness, as a simulated mind would undoubtedly be able to form coherent thoughts upon which it could also reflect.
A definition of consciousness does not necessarily equate to what is defined as human. An argument can be made that animals are conscious using Descartes’s logic, as they respond to external stimuli and have memory systems. The philosophical missing piece of what it means to be human is often called the concept of the self. Descartes would claim humans have an underlying substance, the self, that is comprised of attributes that make each person unique. A helpful analogy is to picture a pin cushion as a representation of the self, and attributes would be individual pins in the cushion. Every human has the same underlying pin cushion, but the added pins contain attributes like hair color, eye color, skills, interests, and memories that make each person unique [9, 10].
Philosopher David Hume defines the self as a bundle of perceptions, a whole made of parts that create a unique individual. This can be pictured like a pie chart, where attributes like hair color and memories are just pieces that make up the entire “pie,” or self. Humans are not one thing, but rather a unique mix entirely different at every level from another person. From a negative interpretation, it also implies that humans have no substantial “self” without all the individual pieces [9, 11].
However, both Descartes’ and Hume’s definitions of the self are not explicitly clear, as they leave no way to prove negative experiential facts. Their definitions allow you to establish what the self is but not what it is not. No experience one can have or observe would disprove the existence of the self. Additionally, Descartes’ definition does not explain the underlying substance of humanity, and Hume’s definition does not explain the bundling relation of attributes.
To fill these gaps, another definition of consciousness is presented in terms of the self by Immanuel Kant. Kant claims everyone has an inner and outer self that form consciousness. One cannot have consciousness without a sense of self or a sense of self without consciousness. The inner self comprises the psychological state and rational intellect, while the outer self includes the senses and the physical world . This would keep with Hume’s theory of the self. However, Kant expands on this by providing a way to prove that something does not have a sense of self. If the subject has an outer self but no inner self or vice versa, it will not have a complete sense of self and, therefore, will not be conscious. Take, for example, a robot that can move and “see” with cameras and sensors telling it when to stop so it does not bump into walls. This robot would have an outer self as it perceives and responds to external stimuli. However, the robot would have no thoughts, memories, or rational thinking and would not have a complete self or a conscious mind [9, 12].
Kant’s definition can be applied to a simulated mind. A simulated mind would comprise the different electrical and mechanical programming that embodies it, but it would have no external perceptions beyond what it is programmed to experience. So, while a simulated brain would have a sense of self and consciousness if given a way to connect with external stimuli, a simple brain scan on a computer would not. A normal brain scan would have an inner self but not an outer self and, through Kant’s definition, could not be considered conscious or human.
It could be argued that “external stimuli” are relative, leading to more profound questions about true perception. If a brain is fully simulated, it would also be possible to simulate a body, an environment, and chemical and hormonal fluctuations that would change its brain patterns. Like current virtual reality, entire environments can be simulated so that they can be seen and heard. These environments can even be felt with adaptive haptic technology such as vests, treadmills, and gloves . A computer can simulate a physical world that can be experienced through the senses, so it is not unreasonable to believe that a digital mind could also exist in these spaces. All these structures would exist outside the brain’s digital reconstruction and be considered external stimuli. This would give the digital mind an “outer self,” making it human, at least by Kant’s definition.
Given these definitions, the question remains whether a functional digital mind is capable of consciousness and a sense of self. External factors that affect the digital mind must be programmed to experiment and learn from a digital simulation. For example, if a simulated brain is used to examine the development of Alzheimer’s, it would be necessary for the brain to simulate aging and the passage of time. Additionally, if the digital consciousness could be asked questions to determine what it can still remember, it would need to be able to interface with the researcher observing it. Therefore, a functional simulated brain will have the potential to develop consciousness and a sense of self.
If brain simulations have the potential to become conscious, it calls into question the long-term ramifications of whole brain emulation. On an individual level, the simulated brain would be a direct copy of a person, and it would maintain the memories and consciousness of that individual. The digital brain could have the same thought process, emotions, memories, and sense of self as the original. Additionally, if the new version could be imported into exceptionally advanced hardware, such as a robotic body, would it believe itself to be alive? Would it believe itself to be the original human subject?
The idea of brain scans retaining the memory and sense of self as the person from whom they were scanned frames whole brain emulation as a future for potential immortality. On a broader scale, this technology allows humans to upload their minds to a digital database where they could live forever. Are researchers creating a world where humanity does not look as it does today? If these simulations are conscious and maintain a sense of self, they would fit into the philosophical and neurological discussion of what it means to be human. It would create a future where people can exist in an exclusively digital environment after their deaths, making a type of post-humanity.
This perspective is often referred to as transhumanism. Transhumanism is the ethical and philosophical movement for developing biomedical enhancements that improve human health and life. This includes medical advancements such as prosthetics and implants, but it also often refers to major alterations to the human body through non-medical technical enhancements. There are two separate sects of transhumanism . The first proposes the emergence of a mechanical superintelligence. The second postulates humanity’s goal, leading to humans becoming dramatically enhanced by genetic and technological improvements . This could lead to “mind uploading” – leaving behind physical limitations and suffering by extending lives indefinitely in a digital world. From this frame of view, whole brain emulation is the ideal future for humanity.
The problem with this theory is that it paints a more optimistic future than reality. Every time a brain is scanned and uploaded to a digital environment, it creates a copy, not a transfer. That means that there will always be the original person left behind. For a moment, the human and its copy would be identical; then, they would become separate individuals as they underwent different experiences . In Kant’s theory of consciousness and the self, external stimuli and memory are integral parts of an individual. In the moments following the scan, both would be experienced differently by the original person and the copy.
The idea of this copy being separate from the original person poses an ethical dilemma. Is the copy human? Is it ethical to create copies for survival or evolution if it means the original will always be left behind? Is the original person considered valuable if the digital copy is seemingly immortal? To frame these questions around an example, imagine a scenario where a person is completely paralyzed. If their brain could be successfully copied onto a computer and then exported to a digital environment or robotic body, that copy would be able to move and function as an able-bodied human. However, the original paralyzed person still exists. Can the copy make medical or other decisions for the original person? How would family members in this situation deal with this new entity? These are disturbing questions, but they are necessary to consider when examining the future of whole brain emulation.
A simple solution is to halt the development of this technology in the first place. However, despite the potential long-term ramifications of whole brain emulation, there are significant short-term benefits.
The ability to map the human mind would provide a deeper understanding of how the brain functions. The Human Brain Project is currently one of the most impressive large-scale attempts at simulating the human mind. They propose that accurate simulations reduce research reliance on animal testing, as they could perform studies in a computer environment instead . Results from animal testing can often be imprecise, leading to humans being harmed in later clinical trials. Computer simulations would eliminate this risk and better predict how a new medicine or medical technology can impact humans .
Additionally, it would be an invaluable tool for studying mental illnesses and diseases of the mind. Being able to perfectly map out the development and impact of Alzheimer’s or Parkinson’s Disease could be used to research potential cures. The company Neuralink is already beginning this type of research. They claim a direct connection to and understanding of the brain could lead to the development of technology that enables paralyzed people to communicate .
Would it be morally acceptable to deny these advancements in medicine simply due to the fear of where this technology may lead? From one perspective, restricting one type of medical research may be the lesser of two evils if it prevents a future where the essence of humanity is called into question. On the other hand, halting progress in this field could indirectly prolong the suffering of those dealing with mental illnesses or neurological disorders. Who makes this decision? Is it fair to current and future patients and their families to overlook a potential cure or aid? There may be no “right” answer to such questions. As with many moral dilemmas, everyone will have a different perspective. A natural death may be preferred to questioning one’s humanity, so perhaps it is best to let individuals make their own choices. Yet, with research on whole brain emulation currently being conducted, a solution must be presented and evaluated to determine what comes next.
Ethical Research and Moving Forward:
Ensuring that WBE research is conducted ethically is both possible and necessary. Research organizations must adhere to standards such as the National Society of Professional Engineers code of ethics and the National Institutes of Health’s guiding principles for ethical research [20, 21]. These values are based on serving the community, respecting the rights of individuals, and ensuring that the benefits of research and design outweigh the risks.
Whole brain emulation and brain simulation research is conducted to improve the quality of life for many people. The controversy surrounding research is not that it is being conducted but rather how it is being conducted. If research into replicating the human mind continues, it must follow a rigorous ethical framework designed by a diverse group of philosophers, health professionals, and engineers. That ethical framework may change as new information becomes available and advances are made. This is why it is essential to continue having these conversations and asking these questions. Technology advances quickly, so a question must be addressed: what kind of future do humans want to achieve?
By Jennah Saqib, Viterbi School of Engineering, University of Southern California
About the Author
At the time of writing this, Jennah Saqib was a sophomore studying astronautical engineering with a minor in cinematic arts.
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