In this post, we will address one of the most important subjects in mathematics. Function is one of the scariest subjects for children, especially in high school. Discourse on the Method (Discours de la Methode) How are we going to start the speech? According to Leibniz and Euler: Creating implies transforming what exists; God created everything and everyone. This way, he would have done his Work optimally. If the answer is affirmative, then any element of nature (physis) is provided with reasoning (methode).