We ended Part One with the idea that the categorical imperative must be the law under which rational beings act. And contrary to Hegel, the categorical imperative is not an empty formalism in the sense that it allows or prohibits everything. Before we move on to the domain problem, I would like to give a short discussion on how the first formulation (the Formula of Universal Law) of the categorical imperative works.
Let’s take Kant’s famous example: you are strapped for cash, need it badly, and the only way to get is to lie to someone (or a bank) that you will pay it back. So, you plan to tell a lie in order to get some money.
The first thing to do is to formulate your maxim, which follows the lines of “I will do Act-A in order to achieve Purpose-P.” The foundation of this maxim is the idea of a hypothetical imperative. A hypothetical imperative is an imperative of the will: If will End-E, then I will the means to that end. Kant believed that this was analytic based on the concept of willing. If you will an end, and you take yourself as a being that wills (that is, as a cause of something), then you must will the means to that end. If you don’t, then how are you taking yourself as the cause of the end? It’s a pipe dream, not a willing, otherwise.
So, we start with a valid and true hypothetical imperative: If I will that I get ready cash, then I will that I make a false promise to repay a loan.” And you turn it into a categorical imperative: I make a false promise in order to get ready cash.
Now what? We imagine what the world would be like if everyone in world adopted that maxim under those circumstances. That is, whenever someone needed money, they would make a false promise in order to get it. This is the World of the Universalized Maxim. Imagine further that this is along the lines of natural law (gravity pulls things to earth) and is well known.
And now the 64 dollar question: can you still act on your maxim? No you cannot. Your maxim fails because, as a practical matter, it no longer works. In the World of the Universalized Maxim, no one is going to believe you when you make your false promise. It will be laughed at as a “vain pretense.” The effectiveness of your false promise depends on you being an exception to the rule that people generally promise truly. Take that general rule away, and promising as an institution disappears. Without people generally trusting promises to repay money, your false promise will be ineffective in gaining any actual money.
Thus, you cannot simultaneously will your maxim and will that everyone adopt it. You have contradicted yourself. Thus, giving a false promise in order to gain ready cash is impermissible.
-Korsgaard, “The Formula of Universal Law” in Creating the