A baby who accidentally touches a spoon while eating will stare at it, curious but not knowing what he is curious about, but if you pick up the spoon and put it back in his hand, he will deliberately touch it.
These repetitive drops are the baby's first understanding of physics.
Drawing: Tomasz Walenta
Human beings create writing and writing so that the discoveries of previous generations can become the knowledge of future generations. Otherwise, to this day, each of us is like that baby, curious but not knowing what we are curious about.
But ignorance is often a good thing for understanding the world. We have walked through the chaos and desolation of "science" before, led by many geniuses to reach today.
Now we know that spoons are made of matter, and they fall because of gravity. And when we become too familiar with the rich world around us, we need to go back to our infancy and abandon all our knowledge of the material world in order to rediscover it.
On February 11, 2016, for the first time, a gravitational wave signal from a binary black hole merger was detected.
Frank Wilczek was a top physicist and grandfather. He has already learned about the interpretation of the material world by his genius predecessors, but he is also extremely envious of the state of his newborn little grandson who knows the world from scratch, and he believes that this innocent ignorance is the ideal state of re-recognizing our place in the universe.
Frank Wilczek
（Frank Wilczek）
He was awarded the Nobel Prize in Physics in 2004 for his achievements in the theory of quark particles (strong action).
In his new book, The Principles of Everything, he writes: "The simple facts of how the physical world works are powerful and bizarre, but the way we think that helps us discover them is equally a great achievement." According to these fundamental laws, what role do we humans play in this grand picture? This is an important question. ”
The Principle of All Things
[Beauty] frank Wilczek by Bai Jiang Zhu Gao Ping translation
CITIC Publishing Nautilus, January 2022
Wilczek invites us to look back and reflect on the journey of generations of minds through the physical world and rediscover it as a reborn baby.
Giant's pace
Long ago, ancient scientists summed up the laws of day and night, the cycle of seasons, the profit and loss of moon phases, and the arrangement of stars, at this time, people simply observed and predicted their changes more accurately.
By the 17th century, "astrophysics" had emerged that described how objects in the sky worked and studied them using mathematical models, a situation that Ptolemy summarized.
Ptolemy, the master of the "heliocentric theory"
Graphs are derived from the network
Copernicus noticed that the values of certain numbers in this summary could be linked together in surprisingly simple ways, and that, under hypothetical premises, these mysterious "coincidental" relations could be explained geometrically, in a deeper guiding principle.
Kepler absorbed Copernicus's ideas and made other important technological changes to Ptolemy's model, creating a geometric model of planetary motion that was both simple and precise.
Google's custom image of Kepler Anniversary
And Galileo, who was concerned with grand philosophical problems, was not satisfied with simple geometric models, and he was more eager to establish a new way of understanding the world. He wanted to understand something precisely, he had to look for the exact mathematical formula that would fully describe his mundane observations, and he eventually found them.
Thus, Newton combined Kepler's geometry of planetary motion with Galileo's dynamic description of motion on Earth, now considered the classic Newtonian theory.
Kepler model
The process of understanding the world is a process of continuous discovery and inheritance.
As Newton put it: "For any person or even any age, it is an overly difficult task to explain all the laws of nature." So it's better to do a little bit of precise work and leave the rest to future generations. ”
When our theories can explain a very wide range of phenomena and achieve harmony in detail, we will never be able to understand nature as the Greek philosophers did. Because we know too much, we can only explore the wider space further.
The edifice of physics has been built?
In the first half of the 20th century, when everyone thought that the big picture of classical physics had been decided, Kelvin said: "At the end of the 19th century, the edifice of physics has been built, and two disturbing dark clouds float in the distance in the clear sky..."
These two dark clouds are relativity and quantum mechanics—Einstein's theory of relativity overturned Newton's view of absolute space-time, and Planck's quantum hypothesis overturned the principle of equal division of energy.
In 1927, the Fifth Solvay Conference was photographed, and this photograph brought together half of the walls (or even "full walls") of the physics community at that time
Planck, second from left in the front row, Einstein in the front row
Quantum mechanics is the spoon of the baby, which breaks the human interpretation of everything since Newton, and beats the human being who thinks he has penetrated the whole picture of physics back to the infant state.
Newton believed that the world was controllable and only needed force. Quantum mechanics, on the other hand, says that the world is made up of fundamental components that follow strict but strange and unfamiliar laws. For example, you can't observe something without changing it.
For example, the Uncertainty Principle, which was proposed by Heisenberg in 1927, is based on the idea that it is impossible for you to know the position of a particle and its velocity at the same time.
Moreover, the uncertainty principle is often interpreted as a philosophical problem, and in Heisenberg's own words: "In the statement of the law of causality, i.e., 'if the present is known exactly, the future can be foreseen', what is obtained is not a conclusion, but a premise." We can't know all the details now, which is a matter of principle. ”
Imagine you and a friend sitting in a very dark room observing a dim light. Adjust this light very, very darkly, such as covering it with multiple layers of cloth. Eventually, you and your friends can only see intermittent flashes. But the time you see the flash is different. Light has been broken down into individual quanta, and each quantum cannot be shared. On this basic level, we feel that the world is different.
Even more subversive, psychophysics reveals that consciousness does not direct the vast majority of action. Alvaro Pascual-Leone did a simple experiment with far-reaching significance.
He let subjects twitch their wrists according to the stimulus requirements, or decide which side of the wrist they want to twitch. For example, if they have decided to twitch their right wrist, their left motor area will be active. In this way, researchers can predict what choices subjects make before the exercise occurs.
Then, a turn to reveal the truth came. Subjects often twitched with the hand imposed by the stimulus, rather than the hand they had originally chosen. And the subjects didn't report that an external force had taken control of them, but rather: "I've changed my mind." ”
Meticulous material studies reveal that the things that make up our bodies and brains—the physical platforms of the "self"—are the same as those that make up the "non-self," and seem to be closely connected, which goes against all of our intuitions.
In our infancy, in the rush to understand things, we also learn to misunderstand the world and ourselves. On the voyage to deep understanding, there is much to be discarded and much to learn.
Is that all?
As early as 1929, the great mathematical physicist Paul Dirac, after dispelling doubts in quantum electrodynamics, had declared: "We know most of the problems of physics and all of them, the fundamental laws of physics on which their mathematical theories are based." ”
Quantum physics prodigy Paul Dirac
Dirac refers to the laws of quantum electrodynamics that apply to matter that assumes to be made of electrons, photons, and atomic nuclei. For more than 90 years, we have conducted countless new experiments in the fields of atomic physics and chemistry, with countless new applications and new discoveries.
As the theory became more rigorous, Dirac's bold claims were not only perpetuated, but also brought closer to reality. As our grasp of the strong and weak forces deepens, the scope of our "basic understanding" gradually expands, that is, most of the "most of the physics problems" become larger. For example, the physics of 1929 had no clear idea of how stars produce energy, or what the forces that hold atomic nuclei together are. Now, thanks to thousands of rigorous experimental validations, we are able to answer these questions with confidence.
The difficulty, Dirac argues, is simply that the application of these laws produces complex equations that are difficult to solve. Modern supercomputers are already well equipped for this job, and with their help, our ability to solve equations in fundamental laws has been greatly improved. Quantum electrodynamics, quantum chromodynamics, general relativity, and equations of weak forces, which are in effect within the framework of quantum theory, have advanced research in many fields, including lasers, transistors, nuclear reactors, nuclear magnetic resonance imaging (MRI), and global positioning systems. This is another way we open the world.
The French mathematician, physicist and philosopher of religion, Blaise Pascal, once lamented: "The universe envelops me through space, engulfs me, and makes me like an atom." ”
Wilczek marveled at the vastness of the universe and the abundance of the human body, writing that the universe is very rich, and this richness lies not only in the "outside" of our cognition, but also in the "inside." We can lament the vastness of the world, and we can also lament the number of sands in the Ganges, but if the reverse is constantly magnified, we are also "universes" to more subtleties, and we are also very large!
Each of us contains far more atoms in our bodies than there are stars in the visible universe, and our brains contain the same number of neurons as there are stars in our galaxy. The inner universe provides a valuable complement to the outer universe.
Exploring the workings of the world is itself a human instinct, and our minds allow us to transcend our natural limits.
Now, let's pick up the spoon on the ground again.