Pierre-Simon de Laplace significantly influenced the development of science and technology during the 19th century. He designed the scientific institutions of the new post-revolutionary France, and it was his signature on the decree that made the use of the decimal metric system mandatory. This scientist gave Newtonian physics a solid mathematical framework and systematized the scattered results of the emerging discipline of probability theory. Modeling the most diverse aspects of reality convinced Laplace that everything in our lives is predetermined: spontaneity and free will, he argued, are just an illusion.