Grounding of the Metaphysics of Morals by Immanuel Kant argues for a priori basis for morality. Kant states that an action is moral only if it is good in itself. Our actions cannot be moral if we have external purposes or goals. One action that Kant believes that is morally wrong is lying. Kant says that it is never morally permissible to lie.
His Categorical Imperative, found in his publishing Groundwork for the Metaphysics of Morals is one of the biggest staples in philosophy of its time. Kant believed that action is judged based on logic and motive, rather than the actual outcome of the action. This was what he labeled as “the good will”, which was the focal point of his theory.