Everything starts from nothing. The fundamental principle is to create a point out of nothing, and a point creates time and space. Time and space create the stars and galaxies, the solar system, and the earth. On Earth, life is created, and humankind emerges. And the existence called 'me' is born. This paper assumes fundamental principles from several facts and tries to explain various phenomena such as the birth process of the universe, the movement of particles, and the double slit experiment. Also, from the similarity between the wave function and the neural network, it was confirmed that the square of the absolute value of the wave function is different from a probability but corresponds to each other like an input and output signal. In addition, it was found that there is a threshold value in the wave function, and through this, the fundamental principle could be assumed much more clearly. In addition, by integrating the mental world, the mathematical world, and the physical world, various phenomena were explained within a single theoretical system called the fundamental principle. This dissertation includes Euclidean geometry, relativity theory, quantum mechanics, the concept of string theory, consciousness, and free will, which are the basic contents for making a theory of everything. There is a lot of content in the thesis, but the conclusion is simple. The conclusion of this paper is as follows. Free will always exists.