What Is a Lie?

Defining different elements of dishonesty.

Posted May 16, 2019

 Wikimedia Commons
Source: Wikimedia Commons

As children, most of us were instructed that lying is bad and that we must never lie. We were admonished when we strayed too far from the truth. When people lie to us, we view them unfavorably and treat them accordingly. In cultures around the world, there are powerful social sanctions against lying. For such a widely denounced behavior, one might expect consensus in our understanding of what constitutes a lie.   

Most people would consider me a liar if I said I did not rob a bank when I actually had. However, some of our dishonesties can be a bit more subtle. I passed an acquaintance at work the other day. As we passed, he smiled and said, “Hi, how are you?” I smiled back and responded, “Fantastic, and you?” I wasn’t being honest. I was not feeling fantastic at all. I was extremely tired and very annoyed by something that had happened earlier in the day. On top of all of that, I was running late. I said I was fantastic when I was not actually feeling that way. Did my statement constitute a lie? How about if I just forced a smile at a familiar face on the street, even if I did not actually feel happy—does that constitute a lie? Should all cases of misleading self-presentations be considered lies?

Here is another example to consider. When Jim’s girlfriend, Gabby, asked him what he did last night, Jim said that he stayed home and watched television. In fact, Jim had stayed home and he had watched television, but he had also invited his ex-girlfriend to come hang out for the evening. They had sex, and she spent the night at Jim’s home. Was Jim’s statement to Gabby a lie? Sure, Jim withheld key information, and Jim certainly treated Gabby unfairly, but did he actually tell a lie? Determining whether a lie has been told or not depends entirely on how one defines lying. So, what is a lie?

 Wikimedia Commons
Source: Wikimedia Commons

The Merriam Webster Dictionary defines lying the following way: “to make an untrue statement with intent to deceive.”  This definition is very similar to definitions of lying found in other dictionaries and well-regarded sources, so I’ll refer to it as the common definition. Lying can be conceptualized as just one form of deception, which is defined as “the act of causing someone to accept as true or valid what is false or invalid.” Thus, lying is always a form of deception, but not all deception could be considered a lie.

The common definition of lying may sound pretty straightforward, but if one considers the definition a bit, they can find clear instances of dishonesty that seem like lies but don’t actually fit the common definition. For instance, Jim’s dishonest statement to Gabby was certainly incomplete, and his statement was clearly made with the intent to mislead, but what he said was technically not untrue. According to the common definition of lying, Jim did not lie.

Consider another example. Gabby wants to go see a movie with Jim, but Jim has no interest in seeing the movie. In order to avoid having to see the movie, Jim tells Gabby that the movie is no longer playing at the theater, which he believes is a lie. Later, Gabby decides to verify Jim’s claim, and finds that indeed the movie is not playing at the theater. Thus, while Jim had intended to mislead Gabby, his statement turned out to be accurate. Did Jim lie? According to the common definition, since Jim’s statement was not untrue, he did not lie.

Imagine that Jim is going on a boat ride with a large group where each passenger is expected to pay $20 when they board. Sneaky Jim slips onboard without paying. Before the excursion begins, the boat captain looks at Jim and the rest of the passengers and asks, “Is there anyone who has not yet paid?” Jim chooses to remain silent and he never pays. Given that Jim made no statement or utterance, the common definition of lying would hold that Jim had not lied.  

On another occasion, Jim tells Gabby that he feels bad about having to cancel their upcoming date, when, in fact, he does not feel bad at all. Is he lying? This appears to meet the criteria of lying—to make an untrue statement with intent to deceive. But is an actress also lying when she convincingly tells the audience that she is sad when she is actually happy? When Mick Jagger sings, “I rode a tank, held a general's rank, when the Blitzkrieg raged and the bodies stank,” is he lying too? After all, the audience is aware of the untruth. We all know that he was not actually a tank commander during World War II. And he knows that we know that. Perhaps the common definition of lying is too imprecise for what most of us mean when we use the word “lie.”

 Wikimedia Commons
Source: Wikimedia Commons

Let’s return to the original question I posed. What is a lie? If we break down the common definition of lying, we can see that three conditions must be met for a lie to occur. First, a statement must be made. Generally, statements are made verbally, but people can make statements via the pen, text, Facebook post, sign language, or any other system in which we share signals or symbols that convey a shared meaning. The second condition is that the statement must be untrue. That is, the information shared in the statement must be an inaccurate description or account of reality. This certainly can happen when people lie, but untrue statements are also made when people are simply ignorant or confused about the state of reality. For instance, Plato and Aristotle stated that the Earth was the center of the universe. We would describe them as misinformed, not liars. The third condition is that the speaker must have intended to deceive. Intent can typically only be inferred, as we are unable to peer into a person’s mind and discern their true intent. However, the intent to deceive is central to most people’s definition of a lie.

As one can see from my earlier examples, there are many instances of dishonesty that may not fit under the common definition of a lie, and some instances that would fall under the definition of lying (such as acting) that don’t feel like lies to us. Some philosophers find the common definition of lying far too restrictive and opt for more permissive definitions that dispense with the requirement that lying entail a statement that is untrue. Thus, the common definition of lying can be revised as “to intend to deceive.” According to this definition, omitting information with the intent to deceive can be viewed as a lie. Likewise, using language that is technically true, but intentionally misleading may also be viewed as a lie. As an example, I could tell you that I went to Harvard. While that language may technically be true, it leaves people with the impression that I was enrolled in college at Harvard, whereas I actually just went there for an afternoon tour when I visited Boston. Perhaps having this more liberal definition of lying better captures the essence or the felt sense of what we mean when we claim that someone has lied to us. The broader definition treats lying and deception synonymously.

Others have taken an even broader view of lying by removing the requirement that a lie be an intentional act of deception. Thus the definition of lying becomes “to deceive.” They argue that a lie can sometimes be unintentional, such as when non-poisonous butterflies mimic the colorful markings of their poisonous cousins, thus appearing unpalatable to birds. I think that this view of lying is too expansive to capture what most people mean when they declare that someone has lied. According to this definition, people suffering from delusional disorders who claim that aliens are spying on them would be categorized as liars. Intention is central to how we view the morality of many objectionable behaviors such as lying. For instance, we perceive a shove as hostile if it is intentional, whereas a non-intentional shove is viewed as an innocent mistake. Perhaps, then, a more restrictive and precise definition of lying would hold more utility than a broader one.

The highly regarded deception researcher, Aldert Vrij, proposed a more restrictive definition. He offered that a lie should be defined as “a successful or unsuccessful deliberate attempt, without forewarning, to create in another a belief which the communicator considers to be untrue.” That definition takes the common definition and adds onto it a requirement that the lie must not include a forewarning. When people go to a play, they know that the actors will be saying things that are not true (forewarning), so actors are not considered liars when they weave imaginary characters or roles. Vrij’s definition also requires intent to deceive, so animal mimicry does not fall into the category of lying. However, Vrij dispenses with the requirement that a lie take the form of a statement. This means that half-truths, omissions, and misleading but true wording can be considered lies. Some take issue with Vrij’s definition precisely because it removes the requirement that a statement be made. He seems to assert that any intentional form of deception is a lie. They argue that according to Vrij’s definition, dying one’s hair would be a lie.

Maybe there is no perfect definition of lying. It may be that we need to just find the definition that best captures the majority of instances that people view as examples of lying. I think that Vrij was onto something very useful with his definition, but I think it is too broad. It includes all manner of deception that most would consider perhaps dishonest, but not a lie. If we add to Vrij’s definition the requirement that a lie take the form of a statement or signal, we might arrive at a definition that best captures what most people mean when they say that some has lied.

I propose that a lie should be defined as a successful or unsuccessful deliberate manipulation of communication, without forewarning, to create in another a belief which the communicator considers to be untrue.

As one can see, many definitions of lying fall short as they seek to perfectly characterize this elusive concept. It is important that we aim for a common understanding of lying. Shared definitions offer much utility, especially in the realm of moral evaluations, as they chart out a clear distinction between the ethical and the unethical. If we hope to set standards for the types of untruths that are allowed and those forms of dishonesty that will be punished, we must start by defining the features of each. If we are going to have moral prohibitions and social sanctions against lying, we should all be clear about what a lie is.


Vrij, A. (2008). Detecting lies and deceit: Pitfalls and opportunities. West Sussex: John Wiley.

Bok, S. (1999). Lying: Moral Choice in Public and Private Life. New York: Pantheon Books.