Mind uploading
Mind uploading is a hypothetical process of whole brain emulation in which a brain scan is used to completely emulate a person's mental state in a digital computer. The computer would then run a simulation of the brain's information processing, such that it would respond in essentially the same way as the original brain and have a sentient conscious mind.
Substantial mainstream research in related areas is being conducted in neuroscience and computer science, including animal brain mapping and simulation, development of faster supercomputers, virtual reality, brain–computer interfaces, connectomics, and information extraction from dynamically functioning brains. Supporters say many of the tools and ideas needed to achieve mind uploading already exist or are under active development, but they admit that others are as yet very speculative, though still in the realm of engineering possibility.
Mind uploading may be accomplished by either of two methods: copy-and-upload or copy-and-delete by gradual replacement of neurons until the original organic brain no longer exists and a computer program emulating it takes control of the body. In the former method, mind uploading would be achieved by scanning and mapping the salient features of a biological brain and then storing and copying that information into a computer system or another computational device. The biological brain may not survive the copying process or may be deliberately destroyed during it. The simulated mind could be in a virtual reality or simulated world, supported by an anatomic 3D body simulation model. Alternatively, the simulated mind could reside in a computer inside—or either connected to or remotely controlled by—a robot, biological, or cybernetic body.
Among some futurists and within part of transhumanist movement, mind uploading is treated as an important proposed life extension or immortality technology. Some believe mind uploading is the best way to preserve the human species, as opposed to cryonics. Another aim of mind uploading is to provide a permanent backup to our "mind-file", to enable interstellar space travel, and to be a means for human culture to survive a global disaster by making a functional copy of a human society in a computing device. Some futurists consider whole-brain emulation a "logical endpoint" of computational neuroscience and neuroinformatics, both of which study brain simulation for medical research purposes. It is discussed in artificial intelligence research publications as an approach to strong AI and to at least weak superintelligence. Another approach is seed AI, which is not based on existing brains. Computer-based intelligence, such as an upload, could think much faster than a biological human, even if it were no more intelligent. A large-scale society of uploads might, according to futurists, give rise to a technological singularity: an exponential development of technology that exceeds human control and becomes unpredictable. Mind uploading is a central conceptual feature of numerous science fiction novels, films, and games.
Overview
Many neuroscientists believe that the human mind is largely an emergent property of the information processing of its neuronal network.Neuroscientists have said that important functions performed by the mind, such as learning, memory, and consciousness, are due to purely physical and electrochemical processes in the brain and are governed by applicable laws. For example, Christof Koch and Giulio Tononi wrote in IEEE Spectrum:
Eminent computer scientists and neuroscientists, including Koch and Tononi, Douglas Hofstadter, Jeff Hawkins, Marvin Minsky, Randal A. Koene, and Rodolfo Llinás, have predicted that advanced computers will be capable of thought and even attain consciousness.
Many theorists have presented models of the brain and established a range of estimates of how much computing power is needed for partial and complete simulations. Using these models, some have estimated that uploading may be possible within decades if trends such as Moore's law continue. As of December 2022, this kind of technology is almost entirely theoretical.
Theoretical benefits and applications
"Immortality" or backup
In theory, if a mind's information and processes can be disassociated from a biological body, they are no longer tied to that body's limits and lifespan. Furthermore, information within a brain could be partly or wholly copied or transferred to one or more other substrates, thereby—from a purely mechanistic perspective—reducing or eliminating such information's "mortality risk". This general proposal was discussed in 1971 by biogerontologist George M. Martin of the University of Washington. From the perspective of the biological brain, the simulated brain may just be a copy, even if it is conscious and has an indistinguishable character. As such, the original biological being, before the uploading, might consider the digital twin a new and independent being rather than a future self.Space exploration
An "uploaded astronaut" could be used instead of a "live" astronaut in human spaceflight, avoiding the perils of zero gravity, the vacuum of space, and cosmic radiation to the human body. It would allow for the use of smaller spacecraft, such as the proposed StarChip, and it would enable virtually unlimited interstellar travel distances.Mind editing
Some researchers believe editing human brains is physically possible in theory, for example by performing neurosurgery with nanobots, but it would require particularly advanced technology. Editing an uploaded mind would be much easier, as long as the exact edits to be made are known. This would facilitate cognitive enhancement and the precise control of the emulated beings' well-being, motivations, and personalities.Speed
Although the number of neuronal connections in the human brain is very large, the frequency of activation of biological neurons is limited to around 200 Hz, whereas electronic hardware can easily operate at multiple GHz. With sufficient hardware parallelism, a simulated brain could thus in theory run faster than a biological brain. Uploaded beings may therefore not only be more efficient but also have a faster rate of subjective experience than biological brains.Relevant technologies and techniques
The focus of mind uploading, in the case of copy-and-transfer, is on data acquisition, rather than data maintenance of the brain. A set of approaches known as loosely coupled off-loading may be used in an attempt to characterize and copy a brain's mental contents. The LCOL approach may take advantage of self-reports, life-logs, and video recordings that can be analyzed by artificial intelligence. A bottom-up approach may focus on neurons' specific resolution, morphology, and spike times, the times at which they produce potential responses.Computational complexity
Advocates of mind uploading point to Moore's law to support the notion that the necessary computing power will be available within a few decades. But the actual computational requirements for running an uploaded human mind are very difficult to quantify, potentially rendering such an argument specious.Regardless of the techniques used to capture or recreate the function of a human mind, the processing demands are likely to be immense, due to the large number of neurons in the human brain along with the considerable complexity of each neuron.
Required computational capacity strongly depends on the chosen level of simulation model scale:
| Level | CPU demand | Memory demand | $1 million super‐computer |
| Analog network population model | 1015 | 102 | 2008 |
| Spiking neural network | 1018 | 104 | 2019 |
| Electrophysiology | 1022 | 104 | 2033 |
| Metabolome | 1025 | 106 | 2044 |
| Proteome | 1026 | 107 | 2048 |
| States of protein complexes | 1027 | 108 | 2052 |
| Distribution of complexes | 1030 | 109 | 2063 |
| Stochastic behavior of single molecules | 1043 | 1014 | 2111 |
Scanning and mapping scale of an individual
When modeling and simulating a specific brain, a brain map or connectivity database showing the connections between the neurons must be extracted from an anatomic model of the brain. For whole-brain simulation, this map should show the connectivity of the whole nervous system, including the spinal cord, sensory receptors, and muscle cells. Destructive scanning of a small sample of tissue from a mouse brain including synaptic details is possible as of 2010.But if short-term memory and working memory include prolonged or repeated firing of neurons as well as intraneural dynamic processes, the electrical and chemical signal state of the synapses and neurons may be hard to extract. The uploaded mind may then perceive a memory loss of the events and mental processes immediately before the brain scanning.
A full brain map has been estimated to occupy less than 2 x 1016 bytes and would store the addresses of the connected neurons, the synapse type, and the "weight" of each of the brains' 1015 synapses. But the biological complexities of true brain function may preclude an accurate prediction of the volume of binary data required to faithfully represent a functioning human mind.
Serial sectioning
A possible method for mind uploading is serial sectioning, in which the brain tissue and perhaps other parts of the nervous system are frozen and then scanned and analyzed layer by layer, which, for frozen samples at nano-scale, requires a cryo-ultramicrotome, capturing the structure of the neurons and their interconnections. The exposed surface of frozen nerve tissue would be scanned and recorded, and then the surface layer of tissue removed. While this would be very slow and labor-intensive, research is underway to automate the collection and microscopy of serial sections. The scans would then be analyzed, and a model of the neural net recreated in the system into which the mind was being uploaded.There is uncertainty with this approach using current microscopy techniques. If it is possible to replicate neuron function from its visible structure alone, then the resolution afforded by a scanning electron microscope would suffice for such a technique. But as the function of brain tissue is partially determined by molecular events, this may not suffice to capture and simulate neuron functions. It may be possible to extend the techniques of serial sectioning and to capture the internal molecular makeup of neurons, through the use of sophisticated immunohistochemistry staining methods that could then be read via confocal laser scanning microscopy. But as the physiological genesis of mind is not currently known, this method may not be able to access all the biochemical information necessary to recreate a human brain with sufficient fidelity.