Spinors in classical mechanics October 1, 2024 Abstract Spinors were first mentioned by Elie Cartan (1913) and were introduced in physics by Dirac. Though it is conventionally assumed spinor wave functions are a consequence of quantum weirdness or relativity, and while on closer inspection they can be seen as having topological origin, it can be shown that the fundamental reason for the appearance of spinorial objects in quantum mechanics is purely geometrical. Spinors are naturally described in the language of Clifford algebra which Clifford himself originally intended to be a universal geometric language. To that end, the Kepler problem of classical mechanics is solved in a Newtonian geometric spirit albeit in a modern algebraic formulation, setting the stage for the formulation of the spinor equation of motion which linearizes and regularizes (removes singularity) the inverse square force equation of motion with universal solutions yielding new applications to perturbation theory. This also leads to new insights and interpretations of quantum mechanical observables, and the geometric nature of fermionic spin 1/2 wave functions.