From the perspective of material objectivity, we can easily distinguish our own appearance and body, and in the social attributes, others will recognize at a glance "It was you!" But in the rare case of two souls imprisoned in a body, our habitual way of knowing is somewhat confused, and instead of pointing to "a person," we need to point to one of the faces to explain who it is.
The picture above is P's, and the Siamese cannot develop so evenly, and the picture below is the Siamese twin sisters Brittany and Abigail, who share the same body and each control one side of the limb.
At this time, the scope of identification of a person or objective "me" is reduced to a head, then it can be expected that if the head is changed to another body, the "I" will not change in nature except for the need for some adaptation, and the main body of the logo is still the head. The reason why this view is widely accepted is because outside of appearance, we generally believe that the memory formed by all the experiences experienced in life constitutes a unique, unique, spiritual self, which is the basis for our ability to have a continuous, uninterrupted "self-existing" feeling, that is, the "experiential self". The development of brain science has led us to realize that these memories, experiences, and feelings are all present in the brain. Well, we can now upgrade the head replacement surgery without replacing the entire skull, only transplanting the complete brain tissue inside it. Imagine that after The operation between Xiaoming and Lao Wang, did Xiaoming wake up in Lao Wang's body? Although in social relations, everyone will point to Lao Wang's body and say, "This must be Lao Wang's right, the things next door can't run you~", we still tend to think that even if a shell is replaced, Xiaoming will not admit his mistake in his heart, and he knows very clearly who he is. Bob's thinking and memory should depend on the structure of his brain, the complex individualized connections between neurons. Suppose that technology can scan all the connections in the brain and copy them harmlessly into another person's brain, without surgery. Now a vegetative patient donated his own body containing his brain, and after a thorough repair of the vegetative person and using it, the scientist copied the results of your brain scan into his brain completely, that is, the two brains are exactly the same. Everything is ok, the "vegetative man" now stands up and stares at you firmly with a surprised look... So, which one is you now? Or are you both present at the same time?
Yes, normally you might deny that even if you are a clone in the exact same biological sense as you, you will argue: "I am certainly different from him, at least, most directly, I look at him and he looks at me, and the feelings in the hearts of both sides are completely, completely different at this moment!!! Self-perception, which only I can truly experience ~" And the memory of all the experiences you have experienced has not yet been conclusively determined in what way it is stored in the brain, either between the synaptic structures of neurons or in the uncertain general object of "consciousness." But it's not that important to the question of the ego, for example: you suddenly lose your memory. You don't know where you are, you don't know anyone, you don't know who you are, but you are fully aware of the existence of yourself. For pure self-awareness, memory is not indispensable. Memory only identifies your social attributes and place in the world, but it does not essentially affect your perception of the feeling of being aware of yourself. Although the currently found amnesiac patients will lose their episodic memory, the world's knowledge and acquired skills are still basically intact, that is, they know that they are surrounded by people, animals, streets, buildings, driving and playing games (but they can't remember when, where, and how to learn, and why they do this). We might as well imagine the special situation in which all semantic and implicit memories are also completely lost, and when the world is ignorant but the intellect is normal, will it have a serious, even fundamental, impact on the cognition of the self? Taking the thought experiment a step further, making a hypothesis that from the moment of birth, a person is locked in a weightless, wide space without any light, positioned by an infrared device, and then allowed the eternal food to float to his side at regular intervals every day. So, this person has no stimulation or experience other than proprioception and the perception of food, when will he develop self-awareness? Or will it never be produced, but just a conditioned biochemical machine? When he was hungry, there was food, which became one of his extremely limited experiences, and at some point it occurred to him that if he was hungry, would there be no food? Using this doubt as a starting point, and then unfolding the fundamentals of doubt, did he begin to think deeply? Will he go to the futile quest to discover the sources of food and begin to explore the world? Is this a sign that consciousness is beginning to awaken? Without any reference, will there be a consciousness of the "self" of the individual? Frankly speaking, I think that this void person can still eventually produce a vague concept of "me" in consciousness based on proprioception, because he can truly perceive and experience that "himself" exists, with a limited perception of the "world". In fact, if this thought experiment is taken one step further, it will dramatically have the possibility of achieving it in reality: that is, cutting off the input and output between all sensory and motor functions and the brain, like a real brain in a vat, and no stimuli and feedback between itself and the outside world will exist, without any feelings and experiences, and even the material basis for generating imagination. The only thing you have, perhaps, is to imagine darkness in the endless darkness... (In fact, in the sensory cortex such as hearing and vision, some noise and flashes may be randomly generated due to occasional firings of neurons, but it is difficult to determine whether the brain can form an effective processing loop without an input signal.) I personally tend to think that in this absolute chaos, states of self-consciousness similar to those we know as never arise, and that neither the neural structures of the brain nor the so-called consciousness are of any use. However, it is not known whether the brain, which is more malleable and adaptable, can develop other forms in extreme difficulties. For the same objective basis, it is important for consciousness research to understand the factors or conditions under which self-awareness cannot be generated, and it is important to be able to narrow the scope of attention by excluding many interfering factors. In other words, it will be easier to understand why you can't and why. But even thought experiments have to have a bottom line, no longer to explore, the annihilation of human nature to get the answer is meaningless, in the universe of life and death everything is not enough (for the question of the loss of control of science and technology, see the link at the end of the article). The formation of self-consciousness seems to depend on "subjective inner sensitivity", that is, "my inner experience", and it is uncertain whether proprioception and external stimuli are necessary conditions for initiation. For clones whose brains and memories are identical, even if their subjective inner feelings are exactly the same, for example, they all think that they are ontology, but the indescribable "subjectivity and inner feelings" are indeed experienced by themselves. That is to say, they all have their own "self-awareness", and in your own view, there will not be multiple "you" at the same time, and "they" are not you. Subjectivity and inner feelings may be both a function of the brain's neural structures and the result of the action of consciousness.
The main structure of our brain is composed of tens of billions of neurons connected to each other, most of which have thousands of dendrites and branches of other neuronal axon endings to transmit signals, forming an extremely complex structure of tens of billions of connections in the brain. Another class in the nervous system that is 10 times more numerous than neurons is glial cells, which mainly act as support, insulate and blood-brain barrier, and glial cells account for more than half of the brain's volume.
Among them, the most important and amazing is the neuronal myelin sheath, oligodendrocytes constitute the myelin sheath in the central nervous system, and Xu Wang's cells act in the peripheral nervous system. During the growth of neurons, two types of glial cells wrap their cell membranes around the axons in concentric rings and extrude the cytoplasm here leaving only the phospholipid bilayer, forming an electrical current insulator around the axon (partially axons with short transmission distances without myelin sheaths). Glial cells form a segment of myelin sheath on the axon, the gap in the middle is called the Lang Fei knot, and the electrical signal is rapidly transmitted along the axon for a long distance. Mammalian nerves can transmit signals at a speed of 120 m/s, which makes the giraffe's brain react quickly and harmoniously to large animals such as hind legs or whales (but Godzilla, who is more than 100 meters tall, is also such a structure, and it takes 2 seconds to be stepped on the tail and react back, and the giant King Kong is not much faster than a sloth). The electrical signal, that is, the generation of action potentials, depends on the different ion concentration gradients formed by potassium, sodium, chlorine, calcium plasma in the process of selective penetration of the cell membrane, resulting in changes in the potential difference between the inside and outside of the cell membrane of neurons; this work is composed of thousands of gated and non-gated ion channels composed of transmembrane proteins and ion pumps that consume ATP for active transport, forming a depolarization (generating action potential) or superpolarization (not easy to generate action potential) process on the basis of resting film potential.
So, how does a neuron know when to generate an action potential? It depends on its numerous upstream neuron inputs. When the action potential reaches the axonal end, it causes depolarization, resulting in the influx of calcium ions and thus initiating the process of neurotransmitter release into the synaptic space, and the receptor protein molecules on the adjacent downstream neuronal dendrites that are connected to it combine with the diffused neurotransmitters, and the active post-synaptic current is transmitted in the neuron cell to the axon of its own axon through electrical tension. The sum of the currents generated by all dendrites on a neuron after receiving upstream axon stimulation, if strong enough, will initiate its axon-generating action potential to continue to conduct backwards. This process is repeated between neurons like dominoes, enabling the transmission of neural signals. The process of accumulating current in the cell can be seen as analog, and the action potential generated is a digital signal.
The fastest responding sensory neurons in our auditory system can fire at 1000 Hz, but we can hear sounds in the 20 to 20,000 Hz range, and dolphins can hear ultrasounds up to 150,000 Hz, but we still know very little about how neurons encode and tune the frequency.
After receiving the neurotransmitter stimulation released by the upstream neuronal axons, the post-synaptic potential generated by the downstream neuronal dendrite may be excitatory (more likely to produce action potential), or it may be inhibitory (not easy to produce action potential), and the stimulation received by different dendrites is not completely synchronized in time, and there are many response mechanisms such as signal amplification, long-term enhancement, sensitivity regulation, etc., which means that a neuron with many dendrites. There are up to thousands of possibilities as to whether their own axons can generate action potentials. The connections between synapses are constantly formed, strengthened, weakened, and disconnected, further increasing the complexity. The brain, made up of tens of billions of neurons, takes this complexity to the limits of what we can imagine. Over the centuries of neuroanatomical and modern research, scientists have determined the function of many brain regions, especially for the primary processing cortex with clear neural pathways such as smell, vision, hearing, somatosensory and motor control; and through the study of many patients with various brain injuries caused by stroke, surgery or accident, we have an in-depth understanding of the advanced processing functions of the brain.
Most notably, many of the functions that we used to think of as belonging to the higher consciousness were also determined by the neural structure of the brain, and the role of consciousness is far less powerful and extensive than people originally thought. For example, in object recognition disorder, G.S., a person with agnosia, although he could not even recognize the most common things before stroke, he could accurately describe the color and shape of the objects in his memory, and he knew that the candle was long, thin, and pink; but when you showed him a real candle, he could not recognize what it was; he reported that it was a "long object", which he thought was a "crayon" when touched with his hand, and corrected it to "candle" after smelling it with his nose. Kevin, who suffered a brain injury, adapted to using his former memories to imagine what was in front of him to compensate for the impact of the recognition disorder on his life. Although he didn't know anything when he stepped into the football field, he could see the green but couldn't recognize the grass, and he coached the local children's football team but didn't recognize the moving white object as a football... But he was able to use his imagination to match the scene in front of him with his visual memory: on a green field, the ball should be round and white, and people should play... But when the players get together and hug and the goal is chaotic, he can't tell what's going on, and what he sees feels like a collage of colors and movements.
Kevin was able to draw objects accurately from memory, but when he showed them to him later, he didn't recognize them at all.
Kevin's phenomenon of complete separation of mental images in memory from real cognition makes what should be "I realize that people are playing football" reduce to the function of neural structures. Frontal lobe damage will cause people's temperament to change greatly, self-control to decline, lose the ability to plan the future, work toward long-term goals or take into account the consequences of behavior, and so on, involving the continuous accumulation of cases involving "personal will and conscious behavior and experience", so that many scientists and philosophers believe that the extremely complex organizational structure and activities of neurons are the whole of our consciousness, thinking, feelings, experiences and spirits, and matter constitutes everything in our body and mind, and there is nothing else. So where does self-consciousness go in monistic mechanism? Or does it not exist at all? Let's look at the objectively undeniable visual experience, which is an important channel for the construction of consciousness, but there is indeed a huge illusion in this regard, that is, a large part of the visual world in our eyes is an "illusion" automatically filled out by the brain.
Cover your right eye, then use your left eye to focus on the dot on the right side of the image above, adjusting back and forth at a distance of about three times the width of the picture, and you can see the blue line segments blending together. This is the brain with the background automatically filled the blind spot field of view, replaced by complex textures can achieve the same realistic and perfect effect? Below is a GIF, after clicking on the white circle there will be a beating red rabbit, or about three times the distance can try.
Most of the cone cells of our eyes are concentrated in the fovea, which means that the field of view that can distinguish the details is relatively small, and attention is the ability to pay attention to some things while ignoring others; in the process of binocular scanning, a large number of details are actually invisible, and the processing ability of the visual cortex is not so strong. Once you re-examine it carefully, you will find that there are many details that have not been noticed, and changing blindness and not paying attention to blindness are more typical phenomena. However, whether wandering the bustling streets or looking out the window on a high-speed train, we have never felt any gaps and absences, and the world is continuous and complete in our eyes, which is likely the result of the brain's automatic filling. So the question is, if the brain already knows what needs to be filled, is the point of doing so that we perceive the whole world? This may be just one function of the brain, but the point is: Will such a function act in other ways? For example: self-awareness. Many monists believe that "self-consciousness" is just a huge illusion, there has never been such a thing, just an illusion produced by neural activity, we are all humanoid biochemical automata. However, there are two fundamental problems with monistic mechanism: Subjectivity and inner experience. Even if we can assume that subjectivity is a function of neural structures that gives us the sense of "I", how exactly do electrical signals from neuronal biochemical activity emerge from the brain's situational images? Even if it is an illusion, it requires a practical mechanism for occurrence. How does the combination of currents of different frequencies and intensities derive rich and delicate emotions such as "so many delicate rivers and mountains, love you to the earth and the heavens"? How do neurons create and like the Alipay balance, which is not directly related to food, water, delicious food, etc., which is not even visible to see, and how do neurons create and like it? Electric current, painstaking combination of processes that can make wine, just to anesthetize yourself, block? Matter, combining the tool of "man", re-creating atomic bombs to blow up "people" and decompose them, if this process is true, the protagonist is really not necessarily "people". In fact, this may just be the basic rules of the universe, but curiosity drives us to figure out how all this happened and gain more power from it. How are conscious subjective experiences generated by the physical activity of nerve cells in the brain? How does the mind emerge from matter? With man's current limited knowledge and imagination, it is not yet possible to establish any possible mechanism of connection between pure matter and the inner feelings experienced by the body. The univariate and half-time paraphenological theory, which holds that consciousness is only a by-product of neural activity, cannot in turn have the slightest effect on neural activity itself, which leads to the second fundamental problem. 2. The origin of self-initiative. When we see a speeding car, we instinctively dodge; when we are burned, we will quickly retract our hands... This kind of response to external stimuli is easy to understand, and for a sufficiently powerful logic circuit, a simple input can indeed produce complex outputs, and through various feedback mechanisms and adaptability, it can get a kaleidoscopic result, which can explain most of the behavior we exhibit. However, for some purely subjective thinking activities and behaviors, how can the brain, a module of material logic, spontaneously produce activities that are purpose-selective and not random events without any clear and direct stimulus input? No input, how to respond? For example, I suddenly want to hum two little songs, and if this kind of behavior is a random combination of events from the brain, then there will also be a situation of "I suddenly broke my mouth and scolded for five minutes while I was alone." If this impulse appears subconsciously, but you control it in time, it means that at that moment, there is indeed some "unknown phenomenon of unknown cause" that affects and changes the real-time biochemical activity of the neural circuit. In primitive societies, the capture of a person outside the tribe and the return of eating can be seen as a conditioned reflex of hunger; in the present, the angry you actively suppress the urge to kill a scumbag, but only because of the legal provisions or moral codes that exist in your mind. If we think that the purely material brain cannot spontaneously produce legal provisions that can be applied, then the rest of the explanation can only be: we do have autonomous consciousness. But what exactly is consciousness? Is it an objectively existing immaterial entity? If so, then there are two fundamental problems with dualism: 1. Unlimited matryoshka dolls. Because we have no comprehension of how neuronal activity produces images or illusions in our minds, there may be a "consciousness" that perceives and integrates these inputs to form our inner sensory experience. It is as if there is a Cartesian theater in the brain, where the streams of consciousness such as sight, hearing, and touch are staged on a screen of thought, and the audience is "consciousness", that is, the real "you".
It, that is, you, is manipulating your physical body.
Just as the analytical study of brain structure is used to illustrate the neural basis of visual and auditory formation, we cannot help but wonder: What structure and function does this "consciousness" have that allows it to "see and hear"? If we find this consciousness in the brain, whether it is tangible or intangible, it will inevitably be further decomposed and studied in scientific terms. Thus arises the question of the infinite cycle of "consciousness of consciousness of consciousness...".
2. Still matter. If there is an independent conscious body, then in addition to receiving neural signals from the brain, it must also be able to have an impact on neural activity, that is, interact with the neurons of matter, otherwise it cannot produce conscious behavior that is actively controlled by itself. However, what can interact with matter must also be matter. (Physical definition: Matter is the physical object and field that make up all the objects in the universe.) Of course, if you wish, you can also think of this effect of consciousness as immaterial magic, mysterious and unknowable, but this is equivalent to abandoning exploration and breaking away from science. From the two fundamental questions that arise from the assumption of consciousness as an entity, it can be seen that the existence of an independent consciousness or soul entangled in neurons is not at the heart of the problem. This is merely a conceptual or comprehensible difference, essentially the same for science: the study of unknown things and phenomena. Even if the mystery is like magic and magic, it is also an integral part of the universe, a basic property, and it is an object that can be studied, but to what extent and whether it can be studied. In the past, clairvoyance, downwind ears, heaven and earth, etc. were cognitive differences caused by different degrees of development, and the form of magic was usually kept pace with the times, and now it may develop to punch a planet, and in ancient times, it was not known what the stars hanging in the sky were. This makes it possible to obsess over questions like the following, which may be interesting and brain-burning, and not much help for the study of consciousness. Intense sadness, instantly drowning you... Wait, the collective firing of a large group of neurons forms an emotion? So, copying this form of discharge into the chip, do I have a sad circuit board? How many emotions will arise in the infinite bits that flow on the Internet every moment? Is a thunderstorm a manifestation of anger? A ball lightning bolt with a short ego ball life? Your toes accidentally kick the leg of the table, and the pain message is encoded and transmitted to the spinal cord. So, is the spinal cord feeling the pain? No, it was the pain message that reached my brain that I felt the pain. So, is it the somatic cortex of the brain that feels pain? No, it was neuronal processing that made me experience the sensation of pain. Neurons process only currents of varying frequency and intensity, and you mean that there are currents in this world that hurt and even howl? And that's you? Who and what is aware of the pain? Conscious subjective experience is indeed far from any material phenomenon we can comprehend, and it is difficult to study how the cerebral cortex, which is functionally localized, forms a unified and integrated sensory experience.
For example, the shape, color, depth and movement of objects in the field of vision are processed differently, and the processing speed of each characteristic is different, but our sense of time and space is smooth and unified, and the addition of auditory and motion control will not feel any separation experience. This physically non-uniform, but subjectively unified phenomenon, which seems difficult to accomplish the task of integration based solely on the interaction speed of neurons, may indeed have a global mechanism of action that has not yet been discovered: the field of consciousness or the field of mind. But it will be highly dependent on neurons, and where part of the brain area is damaged, the field may appear hollow. However, it does not make much sense to forcibly link the problem of consciousness to quantum mechanics at the moment, although it has played a key role in the quantum walk of chloroplast energy transfer, the quantum measurement of odor molecular bond vibrations in the sense of smell, and the quantum effect is likely to exist in the microscopic mechanism of the brain. Although both consciousness and quantum effects are mysterious and unpredictable, they are not necessarily directly related to the mind. For humans whose physical bodies have not yet stepped out of the Earth-Moon system, the mysteries of the universe abound, but what has just happened to be discovered is the quantum effect. The biggest difficulty in the study of consciousness is that it is currently impossible to use any externally observable physical events, or to describe them by any known physical theory, but can only be detected by the subjective feelings of individuals, and brain tissue is only effective if it is "alive", but it cannot really open the human brain to cut and cut on it, and randomly insert electrodes to do experiments. Until a substantial breakthrough is achieved, research can still be carried out using limited, indirect methods. I think a key entry point with a high probability of grasping is the transition between the subconscious and the conscious state. This is a clearly perceived change, and since it is a change, it must be different, and there is a possibility of finding out the relevant things and rules, such as waking up in an actively forced dream (I will write an article on this according to my own experience and try to design an experiment). Whether it is the exploration of the universe's time and space, or the pursuit of the origin of life, although the progress is not great, human beings can at least have ideas, find ways to start, and study step by step. But for the consciousness that each of us has and can personally experience, we have almost no clue or how to start. Among the many possibilities, there may also be an extreme case in which, at the current level of human mental evolution, it is not yet enough to understand consciousness. However, the road of exploration will still be passed down from generation to generation, and the meaning of exploration is not absolutely meaningful, perhaps it is just an explanation and a driving force for the survival of being born as a human being