Disclaimer: Read The Categorical Imperative before reading this.

Kant’s Categorical Imperative offers a reason-based way to make the right decisions within its formulations. However, there are some clear issues with solely relying on the CI. If we remind ourselves of the first rule of the CI, that one should not do any act that could not be a universal law, it can seem overly rigid. One example that tends to be brought up is lying. We can all agree that while lying should not be instated as a universal law, lying is also something that should not be sweepingly labeled as immoral. For example, sometimes white lies can be considered morally justified, or amoral at the least. However, following the CI, one would never be able to lie.

Here is a famous extrapolation of the aforementioned dilemma. Say there is a serial killer knocking on your door, asking where your family is (they are hidden in a closet). Following the first formulation of the Categorical Imperative, you would have to tell the serial killer where they are (because lying is a horrible universal law, and therefore should be avoided). Obviously, this seems to be wrong thing to do. In this scenario, you have two conflicting obligations: to protect your family, and to not lie. The CI gives no clear order of magnitude to resolve these conflicting duties, and therefore one can easily make the wrong choice. This is something that has been continuously criticized regarding the CI, as it leads to what are called “False Negatives”.

By creating a reason based moral framework, Kant has been criticized for overlooking the role of emotions in daily life. It can be argued that by emphasizing the “duties” we have to each other, the relationships and connections we have become meaningless. The CI discards any notion of moral righteousness based on love, loyalty, or friendship, which seems contradictory to what the majority of us define as moral. Think about the last “nice” or “moral” action you did. Was it to someone you had a close connection with? Kant would probably argue that those actions probably weren’t motivated by reason, and therefore not truly moral.

The last major contradiction I can think about to the usage of the CI is war. War should be impermissible—it cannot be universalized without contradiction, and it undeniably treats soldiers as means to political or strategic ends. However, Kant himself does not explicitly condemn war, nothing that just war can be waged. This appears inconsistent. If the CI is the supreme moral law, how can war—the clearest example of using people as means—be morally justified in any case? To me, it seems that Kant is basically saying one should follow the CI, but the greatest offense to the CI is still permitted under some circumstances (but what are those circumstances?) This is questionable at the least, and would make some completely disregard the CI.