So, if you willed that such a maxim of lying should become a universal law, then you would thwart your goal - thus, it is impermissible to lie, according to the categorical imperative.
And because they are universal, Hare argued, they forbid making exceptions. That is to say, there are three different ways of saying what it is.
For Kant, the feature that underlies all four of them is that we should be guided by our rational conception of duty. Empirical intuitions represent sensible objects through sensation, but pure intuitions are a priori representations of space and time as such.
The Autonomy Formula presumably does this by putting on display the source of our dignity and worth, our status as free rational agents who are the source of the authority behind the very moral laws that bind us. So what is this moral law that obligates all rational agents universally and a priori?
For example, suppose I need money for basic need and that I borrowed knowing full well that I could never make it, I promise that I will make a moral that money knowing that if I do not promise we do not give me and yet I need? The largest of these became stars, and the smaller ones became moons or planets.
After determining what maxim one would be basing the action in question on, one then asks whether it would be possible, given the power in an imagined, hypothetical scenarioto choose that everyone act in accordance with that same maxim.