How does the greatest-happiness principle apply to lying?

The greatest-happiness principle, also known as the utility principle, posits that the morality of an action is determined by the extent to which it promotes the greatest happiness for the greatest number of people.1

When applied to lying, this principle suggests that the moral value of an act is not inherent but depends on its consequences. While some critics argue that widespread lying undermines social trust and security, utilitarians acknowledge that there may be specific circumstances where a lie produces better outcomes than the truth. Consequently, for some utilitarians, lying can be considered morally permissible or even obligatory if it serves the general good more effectively than honesty in a given situation.23

To address concerns regarding the instability of individual calculations, many utilitarians adopt rule utilitarianism. This approach evaluates actions based on whether they conform to a general rule—such as the requirement to be truthful—that is itself judged by the long-term consequences of its widespread practice. Under this framework, truthfulness is generally upheld because it fosters a more stable and happy society, though exceptions may still be considered in extraordinary cases.34