Chapter 3 Chapter 1 Introduction

Question: What is the soul? Answer: The soul is a living organism that is separated from the body but possesses intelligence and free will. ① — Roman Catholic Catechism Handbook The amazing hypothesis is that "you", your joys, sorrows, memories and aspirations, your proprioception and free will, are really nothing more than the collective behavior of a large group of nerve cells and their associated molecules, as Lewis Ka Alice in Dewis Carroll's book said, "You're nothing more than a bunch of neurons." This hypothesis is so incompatible with what most people think today that it can Truly considered astonishing.

Of all peoples and tribes, man's interest in nature, and especially in his own peculiarities, has a long history, though in various forms, going back to the earliest recorded times, and certainly earlier than this .This can be judged from the exquisite tombs that widely appear in human beings.Most religions agree that some form of spirit exists after death, and that it somehow embodies the essence of human beings.If the spirit is lost, the body will not be able to work normally. After death, the soul will leave the body. As for what happens in the future, whether it will go to heaven, hell, or purgatory, or reincarnate as a donkey or mosquito, different religions have different opinions. As the saying goes, not all religions agree exactly in the details.This is often due to the fact that they are based on different teachings, such as the contrast between the Christian Bible and the Islamic Qur'an.Despite the differences among different religions, there is at least one broad consensus among them: Human beings do have souls, and this is not just a metaphor.Most people today still hold this belief, and in many cases, it is quite strong and persistent.

Of course there are a few exceptions.One of them was the few extreme Christians who followed Aristotle and doubted whether women had souls or souls with the same qualities as men.Certain religions, such as Judaism, have little concern for life after death.Different religions have different views on whether animals have souls.There's an old joke that philosophers (although they have their own differences) generally fall into two categories: those who own dogs who are convinced that dogs have souls, and those who don't own dogs who deny the existence of souls. However, there are still a small number of people today (including a large part of the people in communist countries) who hold a completely different view.They believe that a soul separate from the body and not obeying the laws of science we know is a complete myth.We can easily understand why such myths arise.Indeed, if we do not understand much about matter, radiation, and the nature of biological evolution, it seems unsurprising that such myths arise.

Why, then, should the basic concept of the soul be doubted?Of course, if the vast majority of people believe in the soul, on the face of it, this in itself is evidence of the existence of the soul.However, 4,000 years ago, almost everyone believed that the Earth was flat.Today, this view has changed radically, mainly due to the progress of modern science.Earth, a small place by our standards today, was considered large at the time, although its exact dimensions were not known.Most of our religious beliefs today have their origins in that era.Any one person's direct knowledge comes from only a small part of the earth.Therefore, at that time, people had reason to believe that the earth was the center of the universe, and human beings were in the leading position in the universe. As time passed, the origin of the earth was gradually forgotten by people.And the time span of the earth that was considered at that time, although very long compared with human experience, is still ridiculously short today.At that time, people believed that the life of the earth was less than 10,000 years, which is not difficult to understand.We now know that its true age is 4.6 billion years.At the time, the stars seemed to be far away from us, presumably fixed in spherical space.And the universe can extend to infinity (greater than 10 billion light-years), which was simply unimaginable at the time (some eastern religions, such as Hinduism, are exceptions. They exaggerate time and distance purely for fun).

Before Galileo and Newton, our knowledge of fundamental physics was primitive.The sun and planets were thought to move regularly in some very complicated way.They therefore have reason to believe that only angels can guide them.What other force could make their behavior so regular?Even into the 16th and 17th centuries, our understanding of chemistry was mostly incorrect.In fact, until the beginning of this century, some physicists doubted the existence of atoms. Today, we already know a lot about the properties of atoms and assign each element an atomic number.We have learned in detail their structure and most of the laws governing their behaviour.Physics already provides the theoretical framework for chemistry.Our knowledge of organic chemistry is increasing day by day.

We admit that we don't really understand what happens at very short distances (within the nucleus), at extremely high energies, and at extremely large gravitational fields.But most scientists agree that this incompleteness of our knowledge is fundamental to understanding the mind and the Has little effect. In addition to basic knowledge of chemistry and physics, earth sciences (such as geography) and astronomical sciences (astronomy and cosmology) have painted a picture of the world and universe we live in that is different from the basic concepts when traditional religions were founded. of pictures.The modern picture of the universe and its laws of development constitute the basic background of current biological knowledge.Over the course of the past century and a half, this knowledge has changed fundamentally.The "Argument from Desgn" (Argument from Desgn) seemed irrefutable until Darwin and Wallace each independently discovered the fundamental mechanisms that lead to the evolution of living things (the process of natural selection).How could the creation of an organism as complex and exquisitely designed as the human body be possible without the help of the design of the most spiritual and wise Creator?Today, that argument is completely obsolete.We know that all life, from bacteria to ourselves, is closely related to activities at the biochemical level.Life on Earth has existed for billions of years, during which time many species of animals and plants have changed, often radically.Dinosaurs are extinct, and where they lived, many new mammals appeared.Today, we can observe fundamental evolutionary processes, both in the wild and in the laboratory.

Biology has advanced by leaps and bounds in this century.With a better understanding of the molecular basis of genes and their precise replication process, and a detailed knowledge of proteins and their synthesis mechanisms, we now know that proteins have strong functions and a wide range of uses. Form the basis of an ingenious biochemical device.Embryology (now often referred to as developmental biology) is the focus of current research.A sea urchin fertilized egg undergoes multiple divisions and eventually becomes a mature sea urchin. However, if the two daughter cells after the first division of the fertilized egg are separated, each daughter cell will develop into an independent, but But smaller sea urchins.Similar experiments can also be done on frog eggs.After the molecules reorganized themselves, two small animals were produced from the substance that should have produced one animal. When this phenomenon was discovered 100 years ago, it was believed to be the result of some kind of supernatural life force (Life Force).On a biochemical basis, it seems inconceivable to explain the dramatic reproduction of organisms in terms of the properties and interactions of organic and other molecules.We now have no difficulty in principle with regard to the mechanism of this process.We had expected the explanation to be complex.The history of science is littered with ideas that some things are inherently incomprehensible (eg "we'll never know what the stars are made of"), and in most cases time will tell that these predictions are wrong correct.

A modern neurobiologist does not need to resort to the religious concept of the soul to explain the behavior of humans and other animals.This reminds one of the question Napoleon once asked when Laplace explained the laws of motion of the solar system: "How, then, does God work?" Laplace replied: "My lord, I don't need This assumption." Not all neuroscientists believe that the soul is a myth, sir John Eccles being a notable exception, but most scientists do believe that the soul is a myth.This is not because they can prove that the concept of the soul is false, but because they do not need this hypothesis at present.From the perspective of human historical development, the main goal of brain research is not only to understand and treat various brain diseases (although this is very important), but more importantly, to grasp the true nature of the human soul.Whether the term soul is metaphorical or real, it is precisely what we are trying to study.

Many educated people, especially in the Western world, also believe that the soul is only a metaphor.A person who has no personal life before conception or after death may call himself an atheist, an agnostic, a humanist, or a heretic, but they all deny the main ideas of traditional religion .However, this does not mean that they usually think of themselves in a totally different way from the traditional way, because old habits of thinking are hard to lose.A person may not be a believer in a religious sense, but psychologically may continue to think like a believer, at least in everyday life.

So we need to put our ideas in brighter terms, the scientific belief that our minds (the behavior of our brains) can be explained by the behavior of our nerve cells (and other cells) and their associated molecules. ①For most people, this is really an astonishing concept, and it is hard for people to believe that we are just a group of nerve cells, even if there are a large number of such cells, and their interactions are extremely complicated, The reader may wish to imagine this point of view. ("No matter what he says, Mabel, I know I'm looking at the world somewhere.") Why are surprising hypotheses so startling?I think there are three main reasons. The first is that many people are not yet willing to accept the approach known as "reductionism", where a complex system can be explained by the behavior of its parts and their interactions.For a system with multiple levels of activity, this restoration process will be repeated more than once.That is, the behavior of a particular part may need to be explained in terms of the properties of its individual components and their interactions.For example, to understand the brain, we need to know the various interactions of nerve cells, and the behavior of each cell needs to be explained in terms of the behavior of the particles and molecules that make it up.

Where does this process end?Fortunately, there is a natural break point.This happens at the (chemical) atomic level.Each atom has a heavy positively charged nucleus surrounded by an organized cloud of electrons.These electrons are light and flexible, and carry a negative charge.The chemical properties of each atom are determined almost entirely by the nuclear charge.Other properties of the nucleus, such as mass number and secondary electrical properties such as dipole moment and quadrupole moment strength, have little influence on its chemical properties in most cases. Generally speaking, the mass number and charge number of the atomic nucleus do not change, at least in the temperature and environment that life depends on.In this case, knowledge of the substructure of the nucleus is unnecessary for the study of chemistry.There is no difference between the atomic nucleus being made of various protons and neutrons and the protons and neutrons being made of quarks.To explain most chemical facts, all chemists need to know the nuclear charges of atoms, and for this we need to understand an unexpected type of mechanics—quantum mechanics, which governs the behavior of tiny particles, especially electrons.In fact, since calculations quickly become extremely complex, people mainly apply various rough "rules-of-thumb" to make a reasonable explanation in quantum mechanical terms.Below this level, we don't need to take risks. (1) There are still many people trying to explain that reductionism does not work.They usually just take the form of fairly formal definitions, and go on to show that this type of reductionism is unreal.What they ignore is that reductionism does not use a set of low-level, fixed thoughts to explain another set of high-level, fixed thoughts.It is not a static process, but a dynamic interactive process.With the development of knowledge, it constantly modifies the existing concepts of the two levels. "Reductionism" is, after all, the main theoretical approach driving the development of physics, chemistry, and molecular biology.It has largely promoted the vigorous development of modern science.Unless we encounter strong experimental evidence that requires a change of attitude, continuing to use reductionism is the only reasonable course of action.General philosophical arguments against reductionism are undesirable. Another philosophical argument that some people like is that "reductionism" includes "misclassification", e.g. in the 2020s they said that considering a gene as a molecule (now we should say part of a paired molecule) is A taxonomic error in which the gene is one thing and the molecule another, the objection now seems quite hollow. ②Classification is not absolute for us, it is just a regulation of people.History tells us that certain sounding classifications can sometimes be wrong and misleading. Recall the ancient and medieval medical classification of the four humors of the human body (blood, mucus, yellow bile and black bile). bile), we're clear. Another reason why surprising hypotheses are surprising is the nature of consciousness.For example, we have a vivid internal picture of the external world: it would also seem a misclassification to see this as merely another way of describing neuronal behavior.But we have seen that such arguments are not always credible. Philosophers are particularly concerned with the question of qualia, such as how to interpret degrees of redness and degrees of pain.This is a very tricky one, and it comes from the fact that no matter how vivid our own perception of red is, we cannot communicate it accurately to other people, at least not normally.If you cannot describe the properties of an object in a definite way, you may have some difficulty explaining those properties in reductionist terms.This is not to say, of course, that the neural correlates of seeing red cannot be explained to you in due course.In other words, it is possible to say that you can only feel red if the neurons and/or molecules in your brain are acting in a definite way.This may explain why you experience vivid color sensations.Why one neural behavior must make you see red and another make you see blue, but not the other way around. Even if it is concluded that we cannot explain the degree of redness (because you cannot tell me exactly how you feel red), it does not mean that you and I see red differently.If we know that the neural correlates of red in your brain and mine are exactly the same, we can make scientific inferences that you and I feel the same way when we look at red.The problem is with the word "strict".The degree of precision we can have depends on our detailed knowledge of the process.If the neural correlates of red depend primarily on my past experiences, and yours and mine are vastly different, then we cannot infer that you and I see red in exactly the same way. Thus, one might conclude that to understand the various forms of consciousness we first need to know their neural correlates. A third reason why the astonishing hypothesis is strange is that we cannot deny the feeling that the Will is free.Two corresponding questions immediately arise: Can we discover neural correlates of events that appear to be free will, and is our will not merely appearing to be free?I believe it will be easier to explain free will once we have first solved the problem of awareness or consciousness. (This issue is discussed at length in the appendix.) How did this extraordinary neural machine (machine) come about?To understand the brain, it is very important to understand that the brain is the final product of natural selection in the long-term evolutionary process. The brain is not designed by engineers, but it can accomplish a lot of tasks in a small space by consuming negligible energy. Ingenious work.Genes passed down to us from our parents have evolved over millions of years and are deeply influenced by the life experiences of our distant ancestors.These genes, and the developmental processes guided by them before birth, determine the basic structure of various parts of the brain.We already know that the brain is not a piece of paper at birth, but a complex structure with many parts already in place.Experience will continue to adjust this roughly determined device until it can perform delicate work. Evolution is not a complete designer.Indeed, as the French molecular biologist Franccois Jacob said: "Evolution is a tinkerer." It builds on previously existing structures, mainly through a series of smaller steps.Evolution is again opportunistic.As long as a new device works, even if it works in a strange way, evolution will adopt it.This means that the changes and improvements that are most likely to be selected by evolution are those that are more easily superimposed on the existing structure.Its final design will not be exhaustive, but rather the addition of a bunch of interacting gadgets.Surprisingly, such systems tend to work better than machines designed directly for a task. A mature brain is a product of both nature and nurture.This is easy to recognize in terms of language.Fluency in complex language is unique to humans, and our closest living relatives, the great apes, have poor language, even after long training.And the actual language we learn depends a lot on the environment and lifestyle in which we grow up. Two more philosophical points also need to be addressed.First, much of the brain's behavior is "emergent," meaning that it doesn't reside in separate parts like individual neurons.Merely the activity of each neuron does not tell much.Only the complex interplay of many neurons can do such amazing work. The word emergent has a double meaning, first of all it has a mysterious color.This means that emergent behavior cannot be understood in any way (even in principle) as the combined behavior of separate parts, and I find it difficult to say what this idea means.The scientific meaning of emergence (or at least that's how I use it) is the assumption that, even if the behavior of the whole does not amount to the simple addition of each part, such behavior can at least in principle be added to the nature and behavior of each part knowledge of how they interact with each other. A simple example is an organic compound in basic chemistry, such as benzene, which consists of six carbon atoms arranged symmetrically in a ring with hydrogen atoms attached to each carbon atom on the outside of the ring.Apart from its mass, the other properties of the benzene molecule are not all a simple superposition of twelve atoms.However, as long as the interaction mechanism of each part is known, its chemical reaction and spectral absorption properties can be calculated.Of course, this requires quantum mechanics to tell us how to do it.Oddly enough, no one gets the mystical satisfaction from saying that a benzene molecule is greater than the sum of its parts.Yet many people enjoy talking about the brain in this way.The brain is so complex and so individual that we may never have a detailed knowledge of how a particular brain works.But we at least have hope of understanding the general principles of how the brain's many parts interact to produce complex sensations and behaviors. Of course, there may be certain important processes that have not yet been discovered.But I suspect that even if we already know exactly how a part of the brain behaves, in some cases we won't immediately understand an explanation for it.Because it may contain many new concepts and ideas that have not yet been clarified.But we don't think, like some pessimists, that our brains are incapable of understanding these thoughts.If these difficulties do exist, I prefer to face them when I encounter them.We have highly evolved and developed brains that allow us to successfully process many concepts that are closely related to our daily life. However, a trained brain can grasp many phenomena beyond our daily experience, such as relativity and quantum mechanics. These ideas It is counterintuitive, but long-term practice enables the trained brain to correctly understand and skillfully process these phenomena.The thoughts about our brains likely have the same basic characteristics.They may seem alien at first glance, but with practice we may be able to manipulate them with confidence. There is no obvious reason why we should not have access to this knowledge of either the individual components of the brain, or how they interact.It is only because of the extreme complexity and variety of processes involved that our progress has been so slow. A second philosophical dilemma requiring clarification concerns the reality of the external world.Our brains have evolved primarily to deal with ourselves and our interactions with the world around us.But is this world real?This is an age-old philosophical question, and we don't want to get caught up in the chatter that it sparks here.I just want to state my own research hypothesis: there really is an external world that is largely independent of our observations of it.We may never fully understand the external world, but we can obtain approximate information about some aspects of the external world through our senses and brain operations.As we will see below, we cannot be aware of everything that goes on in our heads, we are only aware of certain aspects of brain activity.Furthermore, both the interpretation of the nature of the external world and the interpretation of our own introspection can be erroneous. We may think that we know our motives for an activity, but at least in some cases it is easy to explain, We are actually deceiving ourselves. ①When my wife Odile was a little girl, an older Irish woman gave her lessons in religious doctrine.The teacher often pronounces "being" (creature) as "be-in".Odile heard it as "bean" (broad beans).She was genuinely puzzled by the idea that the soul was a living bean separated from the body.But she just buried her confusion in her heart and didn't tell others. ② "neuron" (neunron) is a scientific term for nerve cells (nervecell). ① This idea is not new, and it is particularly clearly expressed in Horace Barlow's famous paper. (1) The main exception is radioactivity: the rare case of one atom changing into another, which occurs in atoms in stars, atomic reactors, atomic bombs, radiation mines (this is rarely noticed), and in specially designed experiments in laboratories. occur.Radiation can produce DNA (genetic material) mutations and thus cannot be completely ignored, but it is unlikely to be an important fundamental process in the behavior of our brains. ②Canadian philosophers Paul and Patricia Churchland (Pauland Patricia Churchland, now at the University of California, San Diego) have answered those arguments against reductionism quite satisfactorily.See related references and reading material. ①I sometimes use the terms Awareness and Consciousness interchangeably.For some special aspects of Consciousness, I prefer to use Awareness (such as Visual Awareness).Some philosophers consider the two terms to be strictly distinct, but there is no agreement on how to do so. I admit that in everyday conversation, when I want to surprise someone, I use "consciousness"; otherwise, I use "consciousness". Use "Awareness".