“Utilitarianism provides the wrong answer to the question “Why should I keep my promise?”” (Feldman, Introductory Ethics, p. 54).

While reading parts of this book, I was struck by this quote. If it is true, it presents a significant issue for utilitarian ethics. On the other hand, perhaps this is true if one understands Utilitarianism only in light of how it is understood by philosophers such as Mill. If one takes the word utilitarian at face value as referring to that which has practical importance, keeping one’s promise is necessary at a very fundamental level. As Feldman notes, “many moralists find this [the notion that it isn’t utile to keeps one’s promise] unacceptable” (Feldman, p. 54). I thought I’d try and explore why this is the case for at least some moral philosophers. Why ought we keep our promises?

The google dictionary definition of a promise is in keeping with what most understand the word to mean. A promise is “a declaration that one will do a particular thing or that a particular thing will happen”. As promises are “declared” they involve communication. This means that words are shared between people who understand one another, and understand the consequences of those words or actions associated with the promise. We do not utter promises to rocks, and promises uttered to even our most beloved pets are empty. Because a promise entails a firm commitment between two or more people (sentient and intelligent beings), we all know that they should not be uttered lightly. This connection of a promise with communication and one’s volitional intent to do something, it is associated with truth and reality at its deepest level.

Josef Pieper quotes Aquinas (ST I, 16, i), “And so do we call all manufactured things “true” because of their orientation toward our knowing mind. We can call a house “true” inasmuch as it conforms to the original idea in the mind of the architect. And a speech can be called “true” insofar as it reveals a true thought. And similarly are the things of nature called “true” as they mirror their primordial forms, which dwell in the mind of God” (Josef Pieper, Living the Truth, p. 42).

Consider then the utilitarian (understood in a general sense) importance of keeping a promise. If the speech of a promise is ‘true’ it discloses an actual commitment or shares certain knowledge between two or more people. If it is true in this sense it conforms and expresses what is real. If one does not keep one’s promises, it means that there has not been true disclosure conveyed through the language, or the knowledge is not accurate or true, and thus that communication is on a basic level ‘unreal’. If it were to become common that it isn’t practical or beneficial for uttered promises to convey actual volitional intent or true knowledge this would result in ever-expanding falsehood and lack of trust in human speech. This degradation of human speech away from what is real and true is nested within broader reality as the quote from Aquinas indicates.

Human society cannot function much less thrive unless the speech we utter discloses what we actually think, know, or intend to do. In this sense, promise-keeping is of extraordinary utilitarian importance.