A False Premise Is a Lie in Truth

Use logic to disassemble a dissembler 's subtle lie.

Posted Dec 20, 2019

Aleksandr Davudov/123RF
Source: Aleksandr Davudov/123RF

A false premise is a form of misdirection. A basic argument consists of a premise, statements or propositions supporting the premise, and an inference or a conclusion. An argument is a collection of state­ments or propositions that attempt to support a premise.

Inference is a process whereby new beliefs are formed based on established beliefs. The premise provides support or evidence for the inference. A liar establishes a false premise to support an inference that is not true.

For example, a liar states, “I am telling the truth because I am an honest person.” In other words, the interviewee said, “I am an honest person (Premise). Honest people do not lie (Argument); therefore, I am telling the truth (Inference).” The truth is, honest people lie. Being an honest person does not necessarily mean a per­son is telling the truth.

Liars create a false premise by ignoring the question presented, asking themselves another question or making a statement, and then answering their own question or responding to their own statement. A military officer was charged with plagiarizing his War College thesis. The school conducted a formal hearing.

The lawyer showed the officer a copy of a thesis presented by a student several years earlier and then presented the officer with the the­sis he submitted. The two papers were remarkably similar. The following exchange was excerpted from the hearing transcript.

Lawyer: Why don’t you take a look at this one? This is a different paper. Do you recognize that paper? It should be your signature on the second page.

Officer: That’s my signature.

Lawyer: OK.

Officer: Do I recognize it as being my paper?

Lawyer: Yes, sir.

Officer: I couldn’t tell you that. It has my signature on the second page. Could I look at it and tell you that I wrote this? No, I couldn’t do it. Not at this point. I just couldn’t—couldn’t do it.

The officer ignored the lawyer’s question. The office posed his own question and answered his question instead of the lawyer’s question. The lawyer asked the yes or no question, “Do you recognize that paper?” The officer responded, “That’s my signature.”

The officer did not answer the yes or no question with a “Yes” or “No,” which signals the possibility of deception. Instead, the officer posed his own question, “Do I recognize it as being my paper?” The officer answered his own question, “I couldn’t tell you that.” The officer admitted in his pre­vious answer that the signature on the second page was his, but now he can­not recognize the paper as being his.

The officer posed a second question, “Could I look at it and tell you that I wrote this?” to which he answered, “No, I couldn’t do it. Not at this point. I just couldn’t—couldn’t do it.” Answering a question with a question signals deception. The officer’s respons­es support the hypothesis that the officer plagiarized his thesis. Identifying the officer's false premise uncovered his lie. 

From the officer’s perspective, his answer, “No, I couldn’t do it. Not at this point. I just couldn’t—couldn’t do it” makes perfect sense. If the officer admitted he plagiarized his thesis, he would face military discipline. At this point, the officer was not prepared to admit he plagiarized his thesis; however, at some point in the future, he would be willing to admit plagiarism.

The responsibility of the lawyer is to discern when, in the future, the officer would admit to plagiarism, and more importantly, under what conditions would he admit to plagiarism. An effective follow-up question would have been, “At what point could you tell me that it is your paper?”

When you think someone is lying. Listen carefully to what the person says and identify the premise of the person's argument. If the premise rings true, then the person is probably telling the truth. If the premise rings false, then the person is probably lying. Using sound logic is the best way to uncover the truth.