The 707 lecture hall of Guohua University was full of students and guests who had come to listen to the lecture, and they were attentively watching the slides on the big screen.

"Do people have souls? There are many different points of view, both ancient and modern, Chinese and foreign. Personally, I believe that although the body will grow old and decay, the soul will last forever, and the body is only a temporary container for the soul. The following is some of the information collected on the Internet, which is not my personal originality, and I will sort it out for you a little.

On the subject of the existence of souls, during the French Revolution in the 18th century, some people were guillotined and beheaded, which was considered the least painful and most humane form of execution by the victors. But according to eyewitness testimonies, sometimes the prisoners' eyes blink and their lips twitch after their heads are cut off. People therefore wonder: Is there still consciousness after death?

In February 2011, a new scientific experiment sparked renewed controversy over the issue.

Dutch scientists claim that one of their latest animal studies may help answer the question of whether souls exist. The study was carried out by scientists at the request of the ethics committee of the University of Nejmegen in the Netherlands, which wanted to find out whether it was humane to kill animals by decapitation. In some scientific experiments, rats have been decapitated without anesthesia (the use of drugs is thought to contaminate tissue samples) in order to study postmortem phenomena. Scientists want to find out how quickly lab rats lose consciousness and thus how much pain they suffer.

A total of 17 mice were used in the experiment, and 9 of them remained conscious and 8 were sedated. The scientists implanted electrodes into the brains of lab rats and then decapitated them while their brain electrical activity was measured. EEG measurements showed that the level of EEG activity in mice began to decline immediately after being decapitated, dropping to half of the pre-decapitation level within 4 seconds (scientists judged that such a low level of EEG activity was a good indicator of complete loss of consciousness, based on an earlier study of awake and sleeping mice). The EEG measurements also showed that the EEG of the 17 mice was different before they were decapitated, but they were completely consistent after being decapitated. This result suggests that awake rats and sedated rats lose consciousness just as quickly after being decapitated. Scientists believe that this could serve as good evidence that decapitation kills animals "humanely" and that decapitation may cause minimal suffering compared to other methods of execution.

Some neurologists believe that a person can remain conscious for a few seconds at most after being decapitated, while clinical evidence shows that a person is completely unconscious within 10 seconds of having their blood flow to the brain cut off. But this time, the Dutch scientists noticed another phenomenon: they continued to track the EEG changes of the mice after they were decapitated, and found that the brain electrical activity of the mice appeared in a 10-second wave, which appeared 50 seconds after the decapitation of the awake mice and 30 seconds for the sedated rats.

Amazingly, similar "death waves" have long been observed in humans. In 2009, a team of scientists from George Washington University in the United States published the results of a study on the electrical activity of seven terminally blind patients before and after their life support devices were turned off. After the hearts of these patients stopped beating and their blood pressure dropped, scientists noticed a sharp increase in their brain electrical activity that lasted for 30~180 seconds. The study suggested that the wave may also reflect neuronal cell depolarization, suggesting that the wave may represent a near-death experience. This inference caused an uproar in the media at the time.

In 1886, the British Medical Monthly published a paper by two PhDs, in which the authors focused on the results of an immediate examination of the body and head of a condemned prisoner after he was beheaded on the guillotine. The article describes it like this:

The condemned prisoner remained calm until the last moment, and his face did not change, even when his neck was under the blade of a knife. Two seconds after being decapitated, his cheeks were still rosy, his eyes were wide open, his pupils were slightly dilated, and his mouth was closed. No fibrous fibrillation, contractions were observed. We put our fingers close to one of his eyes, and his expression didn't change. But when we touch one of his eyes or eyelashes, his eyelids close for the first 5 seconds, just like when he was alive. From the 6th second after the decapitation, such a reflex can no longer be triggered. His jaw was so clenched that he couldn't break it with his hands. No similar muscle contractions were detected on his torso or limbs.

One minute after the decapitation, his face began to turn pale, his torso was still flabby, and the carotid arteries continued to pour blood that remained in the circulatory area. By 4 minutes, his face was quite pale, his upper eyelid was half-closed, and his jaw was no longer as tight as before. The surface of the cut spinal cord is inflamed and cannot produce reflex movements on the trunk or face. No change in 20 minutes. Dissection experiments were then carried out, revealing old signs of pleurisy and alcoholism. The heart chambers are opened, the left ventricle is tightly contracted, the right ventricle is dilated, and there is emphysema at the left lung margin, a phenomenon that occurs almost always in people who have been decapitated. There were bubbles in his leptomeningeal veins and more air in the subarachnoid space. The knife passed through the lower part of the fourth cervical vertebrae.

Our study found that two seconds after being decapitated, he showed no signs of consciousness. Within seconds, the cornea is activated by reflex action. Leaving aside the reflex of the eyelids, the contraction of the jaw and the flow of blood from the carotid artery, this case looks like a corpse being decapitated, and the rest of the condemned prisoner is so sluggish. When blood escapes from the blood vessels, it is natural for air to enter the cranial cavity, which is not expandable or compressible.

Even from the point of view of death struggle, decapitation is such a peaceful and free way. Not even suffocation, death is due to a strong inhibitory effect, just as an animal dies under an overstimulation of the nervous system. In this country, we have a responsibility to destroy lives justly. It is self-evident that this important task should be carried out as mercifully as possible. Compared to beheading, hanging is a very different form of execution. Our instincts are against the executioner, but to replace the unpleasant gallows, we must invent a "calmer and painless way of execution."

From the above description, it is not difficult to see that the two doctors tried to prove that beheading was a more humane method of execution than hanging, and urged the British judiciary at the time to adopt a more humane method of execution. More importantly, they refute the notion that consciousness can exist independently after being decapitated, although they do not explain it.

Leaving aside the truth of this blink of an eye, let's return to the question itself: Does the severed head know its fate, or is it still conscious? This issue has been debated since the guillotine was invented. Some believe that beheading, far from being a quick and painless punishment, is that the person being executed will know that he has been beheaded! One story goes that during the French Revolution, when Charlotte Corday was beheaded for the assassination of Paul Marat, the executioners slapped her with her head, and witnesses saw her cheeks turn red and look angry. Another story says that in the French National Convention there were two rivals, and when they were guillotined at the same time, their heads were put in the same bag, and as a result, they bit each other so that they could not separate the two heads.

Over the years, many scientists have tried to find out through experiments to find out the truth of these early reports, but they have not been able to prove that they are true. In some experiments, the falling human head appears to respond to one's own name or pinprick and so on, but in fact it is likely that it is only an accidental muscle twitch or automatic conditioning, and the root tree does not involve conscious activity. Scientific studies have proven that intracranial blood pressure drops dramatically, causing the decapitated person to quickly lose consciousness. But how long is this "soon"? Fink, the neurosurgeon who does the show on the Discovery Channel, said that the brain can remain conscious for up to 15 seconds after death, which is the amount of time it can sustain before eventual death after the heart stops. Fink also said that people can continue to be alert for a while after their spinal cord is severed. It is impossible for Shanyu to use people to conduct such experiments, so no one can put an end to these mysteries. At present, some scientists believe that a person can indeed last about 13 seconds after being decapitated, and the exact length of time varies slightly depending on the beheaded person's physique, health and specific condition of the beheaded.

Western spiritualists believe that the soul can exist independently of the human body, and they also have a "basis".

On April 10, 1901, a tuberculosis sanatorium in Massachusetts, USA, arrived at a chubby, thin-haired surgeon Duncan McDowell. At that time, tuberculosis was an incurable disease, and the tuberculosis sanatorium was actually a place to die. Duncan is a famous local doctor, but he is not a doctor in this nursing home, and he is not here to treat patients, so what is he here for?

Duncan stooped over a Fairbanks scale, a custom-made 1/10th of a gram scale with a sturdy wooden stand that looked like a camp bed on which one could lie and be weighed, and that was exactly what Duncan had come here to do — he wanted to use it to "weigh his soul." Duncan spent several years contemplating a plan: "If a person leaves his body behind after death and exists in the form of a soul, will the soul take up space?" If it will, then the soul should have weight. In this case, weighing a person at the moment of death, even if the weight is lost slightly, probably represents the weight of the soul leaving the body, right? ”

The death of tuberculosis patients is peaceful, which is in line with Duncan's expectations: "Tuberculosis patients are dying with a long course of illness, running out of energy, dying with little movement, so there is no interference with weighing, and they are already underweight when they die, and we can predict them a few hours before they die." "One afternoon, Patient No. 1 was approaching death and was lifted onto the scale. Duncan and his assistant waited for 3 hours and 40 minutes as they watched as the patient's breath ran out. One doctor observes the patient's chest heaving and the other observes the patient. Duncan himself stared at the scale's indicator. Duncan recorded that "at the moment of his death, the weight on the scale was reduced by 0.75 ounces."

Over the next 5 years, Duncan repeated the same "soul weight reading" experiment on five other patients. In 1907, his paper "The Weight of the Soul" was published in the American Medical Monthly. Naturally, his bizarre claims were refuted by many medical experts, who tried their best to defend them. It has been pointed out that the sphincter and pelvic floor muscles sags when the body dies, so the weight loss may be urine or feces. Duncan retorted that if that were the case, the weight would remain on the scale. It has also been noted that the dying person's end-of-life breath may also cause weight loss. Duncan simply climbed onto the scale bed, exhaled vigorously, and retorted that the scale's reading had not changed.

In the case of "soul weight readings", the most likely cause is "non-dominant loss". The so-called "insensible loss" is the continuous loss of body weight through sweat evaporation and exhalation of water vapor.

Duncan claimed that his experiment had taken this factor into account, and that Patient 1 had lost water at a rate of 1 ounce per hour (only 1/3 of the rate of insensible loss calculated by Sandorias, the proposer of "non-dominant loss"), which was a small weight compared to the 21 grams of the scale reading that had been drastically reduced at the time of the patient's death. So, does the soul really have weight? In fact, Duncan performed the same experiment on a total of 6 patients, but the "21 grams of soul weight" was limited to Patient 1, and the other 5 either said that his judgment of the "moment" of death was not accurate enough, or that various unexpected circumstances occurred in the measurement that invalidated the test data. For example, after patient number 2 was judged dead, the scale reading did not change for 15 minutes and then dropped by 0.5 ounces. In his paper, Duncan said that he suspected that the moment of death was misjudged and therefore the measurement was invalid.

In everyday life we often refer to the word "soul", but in fact we use it in a referential sense, for example, when we say that a person is immortal, we are actually talking about his immortal image and spirit. The existence of a "physical soul" that can both attach to the human body and detach from the human body after death has never been proven. Science, on the other hand, advocates a natural explanation of the observable world, and most scientific research related to the soul only investigates the soul as an object of human belief and an idea, rather than considering the soul as an entity.

When contemporary scientists talk about the concept of "soul" outside of the cultural and psychological realm, "soul" is often just a poetic expression of the mind. Scientists know everything about the "soul" by studying how the human brain works, and they think that the relationship between the human brain and the soul is like the relationship between computer hardware and software, and some scientists use the term "soul" to emphasize that the human mind is more capable than artificial software, or that individuals are qualitatively different from artificial software. What's more, without hardware, software is useless, and without the human body, the soul will be attached?

Some claim to have an "out-of-body" experience, in which "one's soul sees one's own body outside of one's own body." What's going on here? In the 80s, Canadian scientists devised an experiment to experience "out-of-body experiences". The experimenter wears a special hat with coils wound around it to create a magnetic field, but the strength of the magnetic field is only equivalent to the magnetic field produced by an ordinary computer screen. It was found that 80% of the participants felt more or less "consciousness and body separation", such as "their own (soul) flew up to the roof and looked down on their sleeping position", or "their own (soul) even ran out of the laboratory and wandered around the experimental building for a long time". In this regard, the scientist's interpretation is that the presence of a magnetic field affects the temporal lobes of the brain, changing the electrical signals of nerve cells, and these effects cause people to have the illusion of "out-of-body". This experiment, which uses the scientific method to create the sense of separation between consciousness and body, provides a scientific explanation for the "supernatural phenomenon" of "out-of-body soul". No matter how fascinating and authentic some people describe "out-of-body" as merely a human reaction.

To this day, some people still seek the so-called "truth" of various "supernatural phenomena", including the "existence of souls", but science is. If we understand this process, we may be able to protect something far more tangible than the soul—the mind. ”