Grice's Conversational Meta-Maxim: "If C is a conversational maxim, follow it!"

maxim: Generally, any simple rule or guide in our life, but in H. P. Grice and in Kant’s moral theory a practical proposition that connects one’s subjective conditions, that is, one’s reason or motive, to one’s decision to act. Such maxims have the form “I will do A if that will make me happy.” Hence a maxim is a principle upon which one acts. For Kant, there are maxims of action, which express a determination to act in a certain way when a certain condition is met, and maxims of ends, which express a determination to form an intention when a certain condition is met. A maxim is distinguished from a practical law. For a maxim, the conditions (the reason or motives) are subjective and differ among persons because each person has different desires or purposes. For a practical law the conditions are objective, that is, universally valid. Therefore, Kant called a maxim the subjective principle of volition and the practical law the objective principle of volition, that is, the categorical imperative. All maxims have form or universality, matter or plurality, and totality in the complete determination. Maxims must be tested by the categorical imperative. Accordingly, a morally commendable action requires a person to act on a maxim, which can at the same time make itself a universal law so that the subjective principle of volition coincides with the objective principle of volition. “A maxim contains the practical rule which reason determines in accordance with the conditions of the subject (often his ignorance or his inclinations) and is thus the principle according to which the subject does act. But the law is the objective principle valid for every rational being, and it is the principle according to which he ought to act, i.e. an imperative.” Kant, Groundwork for the Metaphysics of Morals