Deontology: What if Everyone Did That?


Maria’s best friend Tammy just bought a new skirt. Tammy asks Maria, “Do you like my skirt?” Maria doesn’t. She knows that telling Tammy the truth will hurt her feelings, but she also knows that lying to her friend is not right. Maria believes in honesty, no matter the cost. Therefore, she decides to tell Tammy that she doesn’t find the new skirt very attractive.


Let’s deconstruct Maria’s thought process. When deciding whether to tell Tammy the truth, she did not consider the consequences of her action, Tammy’s hurt feelings. Instead, she considered the rightness of her two options - telling the truth and lying. Honesty is right, lying is wrong, therefore she decided to tell the truth. Maria’s decision follows the directives of deontology.


Deontology is a moral theory that considers the rightness or wrongness of an action according to universal rules when making a judgment, rather than the consequences of that action.

How It Works

It sounds nice to say, “Always do the right thing,” but how are we to know what that is? 18th century German philosopher and deontologist Immanuel Kant believed that we know what is right by way of our reason. For Kant, right action is both known and obligated to us by our own rationality through the Categorical Imperative – a binding moral rule that operates independently of our personal desires. Unlike hypothetical imperatives, which take the form of “if, then,” such as, “If you want pasta, then you should go to the grocery store,” categorical imperatives give rules for action no matter your desires, such as, “Never tell a lie.” There is nothing contingent on this rule - it holds for every person who comprehends its truth. In this way, reason creates the right, it judges what is right, and it motivates us to do what is right.

Kant formulates the Categorical Imperative in several ways. The most important is known as the Formula of the Universal Law: “Act only on the maxim by which you can at the same time will that it should become a universal law”. This is Kant’s more sophisticated version of our common sense question, “What if everyone did that?” as a guide to action. For an action to be considered “right,” everyone should be able to do the act without a logical or practical contradiction. For example, in Maria’s case, Maria is operating by the categorical imperative, “Never tell a lie,” because if everyone told lies, we could never trust anyone and society would collapse.

The second important formulation of Kant’s Categorical Imperative is called the Humanity Formula and states that “One should always treat rational beings as ends in themselves and never as only a means to an end.” The formulation is usually interpreted as uplifting the rights of other people. Because of the Humanity Formula, deontology is often considered to be a “rights-based” approach to morality. It prioritizes the rights that we have as humans to freedom of choice, movement, beliefs, etc. over the consequences of ensuring these rights are upheld. This is a common criticism of utilitarianism, an approach which determines the rightness of action solely based on consequences. 

However, the rights-based approach is not without its criticisms. For one, Kant’s idea of morality was based in reason, so much so that he believed actions done for reasons other than morality itself are not moral actions. For example, if you visit your grandma because you enjoy seeing her and not because it is your duty to see your grandma, then your action is not moral. Kant does not believe your action is immoral because you do it out of desire, but that it is amoral. Many find this aspect of deontology to be counterintuitive and not reflective of our moral lives. Certainly, we do plenty of moral and right things, such as giving money, spending time with loved ones, and being nice to our friends, because it gives us pleasure, but this does not mean they are not moral actions.

Another criticism of deontology is that rigidly following rules can lead to some confusing outcomes. We can certainly think of cases in which telling a lie would actually be beneficial, perhaps even in Maria and Tammy’s scenario. Since deontology does not give any weight to the consequences of any action, it does not allow for exceptions to the rule. Lying, cheating, and stealing are always wrong, even if doing so would save lives.

Why Care?

Kant’s conception of humans as ends-in-ourselves is particularly important when thinking about human rights. In this way, we have the right to our own freedom and life. Whether we are students interacting with others at school or politicians making public policy decisions, we ought to consider these rights of our fellow humans as more important than the consequences of our decisions. For example, a politician cannot pass a law that states that 10% of the population must give all of their money as taxes while everyone else does not have to pay any taxes at all. While this may maximize pleasure from a utilitarian perspective, from a deontological approach, it requires using 10% of people as mere means and not ends in themselves. 

Although no politicians are suggesting that we alter tax laws so drastically, they are making decisions about where pipelines and factories go, often disrupting those who live on the land and subjecting them to dangerous pollution in order to serve a larger population. From a deontological perspective, some or many of these decisions violate the rights of these individuals, treating them as mere means to an end. Deontology, unlike utilitarianism, attempts to protect our rights as individuals when they do not agree with the interests of the whole.

Think Further

  1. Do you think that moral actions can only be done from duty alone?
  2. Should consequences of an action be considered when determining its rightness or wrongness?
  3. Can we know the rightness of an action from reason alone?


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Learn More

  1. Crashcourse. “Kant & Categorical Imperatives: Crash Course Philosophy #35.” Youtube, 14 Nov 2016,
  2. Driver, Julia. Ethics: The Fundamentals. Blackwell Publishing, 2006.
  3. Ethics Unwrapped. “Deontology.” University of Texas at Austin,
  4. Johnson, Robert and Adam Cureton, “Kant’s Moral Philosophy”, The Stanford Encyclopedia of Philosophy (Spring 2019 Edition), Edward N. Zalta (ed.),