1, Zhi Nuo turtle
Zhi Nuo, an ancient Greek mathematician and philosopher, proposed the tortoise that year. This turtle has one characteristic, you will never catch up with it. It was not until Newton and Leibniz invented calculus that Newton solved the Zhi Nuo Turtle Paradox with calculus.
2, Laplace beast
In Laplace's vision, this god beast can clearly know the motion data and motion state of every microscopic particle in this universe. Then the laplace beast failed. Quantum mechanics developed in the last century shows that our universe is uncertain, and uncertainty is the essence of the universe, so the Laplacian beast died young.
3, Maxwell's demon
This god beast is a monster specially invented to explain the violation of the second law of thermodynamics. This monster can control the movement of a single molecule, make these molecules do work outside, and then realize the second perpetual motion machine. But this Maxwell demon is only an ideological hypothesis.
Schrodinger's Cat
Perhaps the most famous of these four beasts is Schrodinger's cat, the most famous thought experiment in quantum mechanics. This thought experiment tells that if a cat is locked in a box containing poisonous gas, the switch that determines whether the poisonous gas is released is radioactive atoms.
In this experiment, if the reflected atom decays, it will release toxic gas and the cat will be poisoned. Whether this atom decays or not is unknown. If we want to know whether the cat is dead, we can only open this box and have a look.