Final answer:
The first formulation of the categorical imperative, known as the Universal Law Formulation, promotes the idea of universalizability.
Step-by-step explanation:
The Universal Law Formulation of the categorical imperative, which is the first formulation, promotes the idea of universalizability. This formulation states: "Act only according to that maxim through which you can at the same time will that it become a universal law." Immanuel Kant believed that moral imperatives should be applicable to all rational beings without exception, meaning if one considers an action justifiable for oneself, it must be justifiable for everyone when applied as a universal norm. This contrasts with actions taken based on personal desires or outcomes.