[Be sure to read the update to this post in Law and the Multiverse Retcon #2!]

This post was inspired by a question on MetaFilter Projects: “Can you write one on the admissibility of evidence obtained through Professor X’s mind-reading abilities? I’m sure it would implicate Fifth amendment issues as well.” We can analyze this question under the Federal Rules of Evidence. Be warned: this is a long one. The short answer: it’s probably admissible, though hearsay is an issue, and the Fifth Amendment is not a problem.

I. Relevance

First we must ask “is the evidence relevant?” FRE 401 defines relevant evidence as “evidence having any tendency to make the existence of any fact that is of consequence to the determination of the action more probable or less probable than it would be without the evidence.” This is a very low bar, and FRE 402 provides that relevant evidence is admissible by default. But the question must still be asked “is a telepath’s claim about the contents of another person’s head relevant?”

I think the answer is yes. The telepath could be lying, but that’s true of any witness. The telepath’s credibility must be judged by the fact-finder.

The telepath could be a fraud, but the judge could require that the telepath’s powers be proved prior to offering the substantive evidence. FRE 901(a) provides “the requirement of authentication or identification as a condition precedent to admissibility is satisfied by evidence sufficient to support a finding that the matter in question is what its proponent claims.” By way of example FRE 901(b)(9) gives “Evidence describing a process or system used to produce a result and showing that the process or system produces an accurate result.” The accuracy and reliability of a telepath’s power fits that example.

II. Exclusion under FRE 403

Relevant evidence may be excluded “if its probative value is substantially outweighed by the danger of unfair prejudice, confusion of the issues, or misleading the jury.” Of these, unfair prejudice is the greatest risk here.

The notes on FRE 403 state that “‘unfair prejudice’ within its context means an undue tendency to suggest decision on an improper basis, commonly, though not necessarily, an emotional one.” A fact-finder may unfairly prejudice a party by giving undue weight to the testimony of a telepath, possibly completely ignoring the testimony of the original witness. However, “in reaching a decision whether to exclude on grounds of unfair prejudice, consideration should be given to the probable effectiveness or lack of effectiveness of a limiting instruction.” It may suffice for the judge to remind the jury that it should also consider the testimony of the original witness.

III. Personal Knowledge

FRE 602 requires that a witness have personal knowledge of the matter being testified about. This means that a fine but important distinction should be made. The telepath would not be testifying as to the actual events the original witness had personal knowledge of. Instead, a telepath would testify about his or her personal knowledge of what he or she read in the original witness’s mind. It’s the difference between Professor X saying “John Doe shot JR” and “The witness remembers seeing John Doe shoot JR.” Everything the telepath testifies about is ultimately coming through the lens of the original witness’s senses, understanding, and memory.

IV. Hearsay

Now we come to one of the biggies. The general rule under FRE 801 is that “‘Hearsay’ is [an oral or written assertion or nonverbal conduct of a person, if it is intended by the person as an assertion], other than one made by [the person who made the statement] while testifying at the trial or hearing, offered in evidence to prove the truth of the matter asserted.”

A complicated definition, to be sure, but maybe we don’t have to address it. A person’s thoughts are not an oral or written assertion, nor are they a nonverbal action intended as an assertion. Of course, it is likely that in a universe with psychics and telepaths the Federal Rules of Evidence would be amended to include thoughts. Given that, let’s complete the hearsay analysis.

Assuming thoughts fit the first part of the definition, then we know the second part fits as well, since the telepath is not the person who made the statement. The final part is whether the telepath’s testimony is offered to prove the matter asserted. For example, when Professor X says “The witness remembers that John Doe shot JR,” is that being offered to prove that John Doe did, in fact, shoot JR? If it is, then it is hearsay and inadmissible unless it falls under one of the exemptions or exceptions (which are beyond the scope of this post). I will just say that there are many such exemptions and exceptions and that the hearsay rule would not exclude much of any importance.

V. The Fifth Amendment

Amongst other things, the Fifth Amendment protects a person’s right not to “be compelled in any criminal case to be a witness against himself.” This right has some important boundaries, however. The way in which many people think of the Fifth Amendment, “pleading the Fifth,” only extends to testimony by the witness at a legal proceeding. A telepath’s testimony regarding the thoughts of another is not the same as the person’s own testimony. It is the difference between “I shot JR” and “The defendant remembers shooting JR.” So that aspect of the Fifth Amendment would not apply.

However, there is another aspect of the Fifth Amendment, which is the general right to remain silent. That right excludes confessions obtained without first informing a person of his or her right to remain silent during custodial interrogation (i.e. when the person is not free to leave). However, the rule only applies to statements. Other kinds of incriminating information may be extracted, such as fingerprints, mugshots, and DNA samples. A telepath’s reading of a person’s thoughts would arguably fall under the latter, non-statement category.

VI. Conclusion

A telepath or psychic such as Professor X could read a criminal suspect or defendant’s mind, and the information thus learned would likely be admissible evidence and would not implicate a person’s Fifth Amendment rights. During a regular trial the hearsay rule might exclude some such testimony, but much of it would fall under an exemption or exception.