Can the mind exist without a brain

Mind without a brain

Scientists and philosophers have long been concerned with the question of the relationship between body and soul or matter and spirit. The German-Swiss natural scientist Carl Vogt gave a much-cited answer in the middle of the 19th century. In his Physiological Letters he explained, “that all those abilities that we understand by the name of soul activities are only functions of the brain substance, or, to put it somewhat roughly, that thoughts are in the same relation to the brain as they are Bile to the liver or the urine to the kidneys ”.

One of the Vogt here strongly contradicted was Vladimir I. Lenin. In his book "Materialism and Empirio-Criticism" he substantiated his view with the unflattering adjective "vulgar materialistic". For sensations and the thoughts derived from them are not material, but rather subjective images of the objective world, according to Lenin. However, he stuck to one idea. He described mind and consciousness as "the highest products of matter organized in a special way," that is, the brain.

Lenin thereby affirmed his own materialistic point of view, which he contrasted, among other things, with the so-called psychophysical dualism. According to this, in addition to the material body, there is an independent immaterial spirit. This thesis, which can also be found in most religions, is probably the most straightforward solution to the mind-body problem. However, it raises numerous questions to which there are still no satisfactory answers. For example, it is unclear how the energetic mind is supposed to manage to influence the brain causally and to induce the body to take certain actions. In addition, the dualism is incompatible with the theory of evolution. Because an immaterial spirit that exists detached from matter is not subject to any selection processes. A mind as a brain function, on the other hand, can evolve together with the brain.

Although dualism has increasingly lost its acceptance due to such difficulties, our everyday language is still largely dualistic. For many, this gives the impression that the mind, understood, for example, as a kind of software, can be detached from the hardware of the brain and transported elsewhere. Science fiction films feed that hope. In the US film »Transcendence«, the spirit of the fatally injured protagonist is uploaded to a computer, where it finds access to the Internet to spread the word. In the French film »Lucy«, a woman who, thanks to a drug, can control 100 percent of her brain power, manages to transfer her ego to a USB stick.

The related problem of digital immortality is also pursued by serious scientists, although the task of transferring a working copy of the brain to a computer would be gigantic. The human brain has around 86 billion nerve cells (neurons), each of which is individually networked with other nerve cells via around 10,000 synapses. That is, a person's experiences and memories, as well as some personality traits, are represented by a unique pattern of tens of trillion synapse connections called a connectome.

The task of copying a connectome has long been committed to the physicist Sebastian Seung of Princeton University. He still uses mouse brains for this, but believes that his method can also be used on humans. First, the brain is cut into wafer-thin slices with a high-precision knife, which are then scanned in sections by an extremely powerful electron microscope. After the enlarged images created in this way have been saved on a computer, they are placed on top of one another and the cells connected across the slices. This creates a three-dimensional model of the respective brain section, which shows what is connected in which way.

If you wanted to copy a human brain using this method, you would need a storage space of one zettabyte. That corresponds to the amount of information stored worldwide today. Regardless of this, the American neurobiologist David Eagleman invites you to a thought experiment: "Let's look far into the future and imagine we could make an image of a special connectome." Would the information obtained be sufficient to represent the person belonging to it? Could this snapshot of every circuit in the brain evolve into consciousness? No, says Eagleman. “The circuit diagram is only half of the living brain. The other half is the electrical and chemical activity between the connections: messenger substances are released, proteins change their shape, electrical current flows through the axons of the brain cells. «These processes also make a person so special and unique. And they are often the result of physical activity and social interactions that affect the brain in unpredictable ways.

Obviously, to understand consciousness, it is not enough just to consider the fine structure of the brain. The approach of understanding mind and consciousness as emergent properties of the brain is more promising. Emergence (lat. Emergere = to appear) is understood as the spontaneous development of new properties of a system as a result of the interaction of its elements. The following applies: The emergent properties of the system do not apply to any of its elements and cannot be fully traced back to their properties. Behind the phenomenon of emergence hides, if you will, a dialectical process in which quantitative changes in a system lead to the emergence of a new quality. To be alive would therefore be an emergent property of the biological cell. And what is commonly called consciousness, an emergent property of complex neural systems.

With such a view, however, it is important to avoid some misunderstandings, emphasize the philosopher Mario Bunge and the biologist Martin Mahner in their book "On the Nature of Things", which is well worth reading. "If we speak of emergence in terms of mind and consciousness, then we do not mean that the brain produces, as it were, a spiritual substance that somehow exists as an independent thing next to or above the brain." Rather, consciousness is the inner aspect of certain complex neural systems that From the outside, nothing can be seen but neurophysiological processes. Or to put it another way: In the subjective experience of the individual, also called the first-person perspective, only the mental is present, for example the color red. In contrast, the objective observation, i.e. the third-person perspective, only reveals a complex networked system of Neurons. In a nutshell, one could say: colors like red are the qualities of experiencing electromagnetic radiation in an actually colorless world that are evoked by the brain.

When interpreting emergent processes, the idea that the brain causes consciousness often resonates. Here, too, Bunge and Mahner contradict: "A causation is only present if an event in one thing A produces an event in another thing B." However, the emergence of consciousness in complex neural systems cannot be understood as a causal production. Rather, consciousness is a special property of those systems and therefore cannot be separated from them and transferred. Nor can it interact directly with other things or systems, as esotericists like to assert. Because that would run counter to the law of conservation of energy.

The view that consciousness is an emergent property of the brain does not say much about its nature. Nonetheless, it makes an important contribution to the naturalization of the psychic. Because as a result, the appearance of consciousness is understood as something regular, for which no supernatural ingredients are required, emphasize Bunge and Mahner, who also call their conception emergent materialism.

According to this, consciousness is indeed no fiction, but it also does not have an independent existence separate from the biochemical substrate of the brain. The advocates of so-called functionalism in the philosophy of mind see it differently. For them, consciousness is not tied to any biomaterial, but to the structure realized in a system. As a result, any system with the corresponding complexity and networking could also develop awareness. First and foremost, artificial neural networks should be mentioned here, which are currently being investigated in particular in the context of research on artificial intelligence. Some scientists even claim that a kind of consciousness can develop in an extremely large city. Eagleman describes how this is to be understood: “Just think of the many signals that run through a city: telephone cables, fiber optics, sewers, every handshake between people, every traffic light and so on. The extent of interactions in a city is definitely comparable to that of the human brain. "

Such analogies, which are sometimes seriously discussed, do not convince Bunge and Mahner: "Thinking and consciousness are sequences of changes in the state of certain neuronal systems and only systems of the same type can undergo changes in state of the same type." extraterrestrial beings exist that have developed a nervous system under evolutionary conditions that allows consciousness. In some animals, the complexity of the brain also seems to be sufficient to generate conscious processes. On the other hand, whether consciousness can also arise in systems that are not biotic in nature and have not gone through an evolutionary history can be doubted until the contrary is proven.

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