In 1687, Newton published The Mathematical Principles of Natural Philosophy, a collection of the first scientific revolution, considered to be the greatest scientific work in ancient times, which marked the establishment of Newton's classical mechanical system and heralded the advent of the scientific era. And the book also explains Newton's cosmology, Newton believes that the world is like a clock, when the clock master finishes assembling, the clock is clocked, and then the clock will operate on its own, and the master will not ask any more questions.
Newton's cosmology, also known as the mechanical cosmology. In this world, After God has completed the creation of all things, he retreats into the background, but does not ask the world, and human beings can use his reason to discover the natural laws of the world. So Newton has always believed that there is a first driving force in the universe, and he said this: "All things must have the first driving force when they begin to move, that is, the Creator." That is, after God (the first driving force) has clockworked the whole universe, the whole universe begins to function on its own. The first thrust helped Newton solve the questions of how the solar system formed and why the Earth orbited the sun.
The mechanical cosmology reveals that humanity believes that with the progress of scientific rationality, human beings will break away from the ignorance of the past and enter a new era in which everything can be controlled by human beings and society continues to progress.
Einstein was also a proponent of this mechanical cosmology, and in Einstein's view, the contingencies in so-called random phenomena or probabilistic events are purely characteristics of human cognition. Everything in the world has its laws of development, and Einstein's theory of relativity, although it overturned Newton's absolute view of space-time, still retained a strict causality and determinism.
After Newton's death, classical mechanics had great success in describing the world, and people gradually believed that the world could be mechanically described by the laws of physics. At the extreme, it was Laplace, who proposed the Laplace Creed on top of Newton's mechanical cosmology.
Laplace was the main founder of celestial mechanics, one of the founders of astrochemistry, and the founder of analytical probability theory, so it can be said that he was a pioneer of applied mathematics.
Laplace is more extreme than Newton, Newton also believes that there is a first driving force in the universe, and Laplace believes that everything in the world (including human beings and society) cannot escape the control of the definite laws of physics, so there is no God, and everything in the world moves and develops according to its existing laws, so he believes that there is no God in the universe.
Therefore, Laplace had to focus on solving the problem of the formation of the universe, so he wrote two books, "Cosmic System Theory" and "Celestial Mechanics", and the term "Celestial Mechanics" was born here. Laplace believed that the solar system formed from a primordial nebula. The primordial nebula forms a primordial fireball due to the mutual attraction of motion and particles, and the primordial fireball further contracts, and due to the combined effect of attraction and repulsion, it gradually differentiates into the planets of the solar system, and finally constitutes the current solar system.
He calculated the characteristics of the solar system, profoundly explained the motion and orbit of the planets in the solar system, and he also applied Newton's law of universal gravitation to the entire solar system. His doctrine, full of mathematical and mechanical theories, was very convincing and gradually recognized by the scientific community. The nebula theory brought about a change in the cosmology, stating that the universe developed and arose in the movement of nature itself, expelling God from the universe.
So when Napoleon asked Laplace why there was no God in his doctrine, Laplace proudly said, "I don't need that hypothesis."
It was precisely because of Laplace's success in using mathematics to explain the celestial stars that Laplace became more convinced of the mechanical cosmology, so he later proposed the Laplace Creed, also known as determinism.
Laplace's creed is the assumption that if an intelligent organism could determine the present state of motion from the largest celestial body to the lightest atom, the past and future states of the entire universe could be deduced according to the laws of mechanics.
The birth of Laplace's Creed released one of the four great mythical beasts in the field of physics, the Laplace Demon.
Laplace pointed out that we can think of the present state of the universe as its past effect and its future cause. If an intelligence knows the forces of all natural motion and the position of all naturally constituted objects at a given moment, and if he can also analyze this data, then the motion of the largest object to the smallest particle in the universe would be contained in a simple formula. Nothing will be ambiguous to this wise man, and the future will appear before him as it did in the past.
Simply put, there is a wise man who can clearly know all the matter in the universe at a certain moment, including the exact position and momentum of each atom in the universe. He could know the state and position of movement of all matter, as well as the forces it received. Newton's laws can also be used to show the entire course, past, and future of cosmic events. And this wise man also has enough computing power to analyze and process data!
This wise man is the Laplace Demon, who was born on the basis of the reversible processes of classical mechanics. Reversibility refers to time inversion, i.e. processes proceed in reverse order. In the equations of motion of classical mechanics, replacing the temporal parameter t with -t means that the process goes through all the original states in reverse order and finally returns to the initial state.
It is precisely because of the reversibility of the mechanical process that laplace can do nothing to overwhelm him, he has nothing to be vague, everything is knowable, and the future will only appear in front of his eyes like the past!
Scientists were initially heavily influenced by determinism (the Laplace Creed) and were convinced of the existence of the Laplace demon, whose "scientific hypothesis" once dominated all Western science.
But by the middle of the 19th century, with the development of thermodynamics, scientists found that from a thermodynamic point of view, all complex thermodynamic processes in nature were macroscopic irreversibility. The macroscopic phenomenon of irreversibility arises because, when a thermodynamic system is complex enough, the interactions between the molecules that make up its system cause the system to evolve between different thermodynamic states; and due to the high randomness of a large number of molecular motions, the way in which the composition and arrangement of molecules and atoms change is very difficult to predict. The evolution of thermodynamic state requires molecules to work with each other, and the process of doing work is also accompanied by energy conversion and the loss and dissipation of a certain amount of heat caused by friction and collision between molecules, and these energy losses are irreparable.
Clausius' 1854 essay " A Modified Form of the Second Fundamental Theorem on the Theory of Thermodynamics " proposed new physical quantities to explain this phenomenon , formally named entropy in 1865 , denoted by the symbol s.
Clausius, proceeding from the efficiency of the heat engine, realized that positive transformation (work into heat) can be carried out spontaneously, while negative transformation (successful thermal transformation) as a positive transformation cannot be carried out spontaneously. The occurrence of a negative transition requires a positive transition to occur at the same time, and the energy of the positive transition is greater than that of the negative transition, which actually means that the positive transition in nature cannot be restored.
Thus Clausius proposed another formulation of the second law of thermodynamics, also known as the principle of entropy increase, that is, the micro-increment of entropy in irreversible thermal processes is always greater than zero. In natural processes, the total degree of confusion (i.e., "entropy") of an isolated system does not decrease.
In short, the entropy of the isolated system never decreases automatically, and the entropy does not change in the reversible process and increases in the irreversible process, which can be said to very clearly point out the direction of the irreversible process.
The reversibility of mechanical processes is guaranteed by universal mechanical principles. But the second law of thermodynamics is also universal, and therefore this contradiction cannot be explained by the fundamental concept of force. The existence of the Laplace Demon was thus shaken!
And at the beginning of the 20th century, Heisenberg proposed the uncertainty principle, Laplace demon was destroyed by the geodetic, before saying Heisenberg's uncertainty principle, we first come to popularize the Planck constant, Planck's constant is a very important natural constant in quantum physics, but also a physical constant, it can be said that in the description of the quantum (a physical quantity If there is a smallest inseparable basic unit, then this physical quantity is quantized, and the smallest unit is called quantum, is the smallest unit of energy) has a very important position in terms of size, is the famous German physicist and founder of quantum Science Max. Planck 1900 found.
Planck discovered that the emission and absorption of electromagnetic waves was not continuous, but carried out one by one, and Planck came to the conclusion that the world was discontinuous
Planck's constant, denoted h, is a physical constant used to describe quantized, microscopic particles, such as electrons and photons, that have a continuous range of possible values under a given physical property. Voted by the 26th International Conference on Weights and Measures (CGPM), the exact number of Planck's constant is approximately: h = 6.62607015× 10-34 j·s
The theory is that you cannot know the position of a particle and its velocity at the same time, and that the uncertainty of the particle's position must be greater than or equal to Planck's constant divided by 4π, suggesting that particles in the microscopic world behave very differently from macroscopic matter.
Can you understand this picture?
Heisenberg pointed out that to measure the position and velocity of a particle, it is best to measure it by shining light on a particle, and a part of the light wave is scattered by this particle, thus indicating its position. But it is impossible to determine the position of the particle to a smaller extent than the distance between the two crests of light, so in order to accurately determine the position of the particle, a short wavelength of light must be used.
But Planck pointed out that you can't use any small amount of light, at least one photon, which will perturb the particle and change the speed of the particle in an unforeseen way.
So, in simple terms, if you want to determine the precise position of a particle, then you need to use a wave with a wavelength as short as possible, so that the greater the disturbance of the particle, the less accurate the measurement of its velocity; if you want to accurately measure the speed of a particle, then you need to use a wave with a longer wavelength, then you cannot accurately determine its position.
So in summary, the experiment you choose to determine the position of the electron itself causes you to be unable to make precise measurements of the momentum of the electron! The Copenhagen faction, led by Bohr, believes that this uncertainty principle is caused by the uncertainty inherent in nature!
Quantum mechanics tells us that physical quantities are uncertain and cannot be measured accurately without error. And the later chaos theory is to smash the Laplace demon to smash, speaking of the chaos principle, everyone should know the butterfly effect.
Chaotic phenomena refer to the seemingly random irregular movements that occur in deterministic systems, and the behavior of a system described by deterministic theory is uncertain, unrepeatable, and unpredictable.
Like the butterfly effect, a butterfly flapping its wings will cause a hurricane. A small error will be contrary to the actual situation!
Celestial orbital mode
Therefore, the existence of the Laplace demon was completely denied, and the reason why the Laplace demon existed was because everyone at that time enshrined classical mechanics as the Bible, and Laplace applied classical mechanics to celestial bodies without any deviations, so Laplace firmly believed that all the changes in the universe would be contained in a simple formula.
It is precisely because Laplace successfully popularized classical mechanics to celestial bodies that he is convinced of his determinism.
The killing of Laplace's demon also shows that the entire universe is full of too many unknowns and unpredictability. If the Laplace demon exists, then the world is too terrible: you and I can all be calculated, our fate is strictly determined by the laws of physics + initial conditions, nothing will be outside the calculation, then what fun is there in life?
Science continues to develop and accumulate in bit by bit trial and error, and truth is never achieved overnight.