A Kantian application to the prisoner’s dilemma:
One might think that Kant’s categorical imperative usually represents him in a very good way. Likewise, the voluntary resignation seen as a universal law is irrational, so we must cooperate. Although, if you take into account that we should not do anything that can not be a universal law independently, one might feel disgusted. The universal renunciation is irrational because the goal of all is to gain value, because if they were indifferent to this value we could rationally universalize that renunciation. So, it is attractive to mention that the objective of our own interest maintains more relevance in choosing the Kantian response to the prisoner’s dilemma than the will as a universal law. But if you consider that you should treat other people as ends and not as means, this dilemma seems to have a solution, to renounce is to treat the other agent as a means to our end. Therefore, we must cooperate.
An example about breaking promises:
If one should not do anything that can not be a universal law, the reason for the promises is to build trust because if they all broke, none would trust those unfulfilled promises and their nature would be exposed. Thus, given that you can not universalize unfulfilled promises, you should not break any promises. To give the word is to acquire a commitment and that is that the obligation acquires value. If one did not care about the value, we would not make promises.