Actions are contrasted in conformity to duty with actions done from duty. This distinction emphasizes the difference in what moral motives and intent are made of. An effort — done from duty — no matter how admirable and amiable it might seem to be — when performed by a sympathetic philanthropist, holds no true moral worth as it is done from duty. The compassionate philanthropist does not incline to do so; instead, they do it out of necessity.
Hypothetical imperatives are moral commands based on the personal will or something available for one to will. Categorical imperatives are moral commands that carry an objective necessity inherent to them, regardless of one’s choice and motives. The imperative is hypothetical, given that the moral order is good as long as it is a means to achieving something else. An action in question is categorical if it is perceived as good in itself, and its will conforms to reason.
One of Kant’s categorical imperatives is the principle of universalization. Shafer-Landau (2017) writes that one should “act only in accordance with that maxim, in connection with which you can at the same time wish it to become a universal law” (p.12). If you perform some action, then everyone else should be able to do so. Lying cannot be adopted universally: it would be self-defeating as people would stop believing one another.
According to Kant, lies are wrong; lying corrupts the quality of human-being. Secondly, a lie damages another person’s freedom to choose rationally. Kant argues that if a person’s decision-making is affected by another person’s lie, that means this other person harmed the autonomy of the person. We have to believe other people to be the recipients of our actions and, conversely, have faith that other people consider us to be the recipients of the consequences of their actions. This would lead us to have a duty not to lie; it would make not lying a categorical imperative, something that is inherently good.
It is possible to lie in situations where one cannot be aware of the consequences of one’s lying. Then, the lie takes over the concept of “one’s own life” and leads to results that people cannot control. It is complicated for a person to objectively assess the benefits and harms that lying would bring in some situations.
References
Shafer-Landau, R. (2017). The Ethical Life: Fundamental Readings in Ethics and Moral Problems. Oxford University Press.