An Epistemological Argument Against Federal Rule of Evidence 403's Cumulative Evidence Clause

• Author: Nathan Kooker
• Position: J.D. Candidate, The University of Iowa College of Law, 2018; B.A., The University of Iowa, 2015
• Pages: 1753-1776

1753

An Epistemological Argument Against

Federal Rule of Evidence 403’s

Cumulative Evidence Clause

Nathan Kooker*

ABSTRACT: This Note presents an epistemological analysis of Federal Rule

of Evidence 403’s cumulative evidence clause, which provides for the

exclusion of concededly relevant evidence where probative value is outweighed

by the risk of needless cumulation. While courts vary in their application of

the clause, it generally affords trial judges the discretion to bar admission of

evidence that will not further assist the jury in reaching factual conclusions

in light of what evidence is already on the record. This Note questions the

wisdom of delegating this power to the bench. If the duty of a juror to form

reasonable beliefs is best explained by an evidentialist view of epistemic

justification, then it seems there can be no principled way for judges to

determine whether a piece of legal evidence might bear an impact on juror

fact-finding. The rule therefore contemplates an unwarranted judicial

guesswork that risks exclusion of potentially important evidence, leaves juries

ill-equipped to perform their duties, and may deprive the parties of fair and

accurate verdicts. Amending or eliminating the ru le to avoid these dangers

would come at no cost to federal trial practice.

I.INTRODUCTION ........................................................................... 1754

II.FEDERAL RULE 403 ..................................................................... 1755

A.THE CUMULATIVE EVIDENCE CLAUSE AND ITS

MOTIVATIONS ....................................................................... 1756

B.A SAMPLING OF INTERPRETATIONS ......................................... 1759

III.AN EPISTEMIC PROBLEM WITH A PRACTICAL IMPACT .................. 1761

A.EVIDENCE AND JUSTIFICATION ................................................ 1762

B.EVIDENTIALISM AND THE JURY TRIAL ..................................... 1765

*

J.D. Candidate, The University of Iowa College of Law, 2018; B.A., The University of

Iowa, 2015. Thanks to Zach Sanderson, Jon Landon, and Jake Schunk, whose generous

mentorship and encouragement were hardly betrayed by their objections to this Note. Additional

thanks to the capable editorial staff of Iowa Law Review Volume 103.

1754 IOWA LAW REVIEW [Vol. 103:1753

C.THE CUMULATIVE EVIDENCE CLAUSE’S ANTI-EVIDENTIALIST

IMPLICATIONS ....................................................................... 1768

IV.ADDRESSING THE PROBLEM OF THE CUMULATIVE EVIDENCE

CLAUSE ....................................................................................... 1772

A.SOLUTIONS TOWARDS RISK-FREE EVIDENTIARY RULINGS ......... 1772

B.THE PRICE OF BETTER FACT-FINDING ..................................... 1774

V.CONCLUSION .............................................................................. 1776

I. INTRODUCTION

When it comes to determining how much evidence is necessary to prove

a point at trial, there is a fine line between helpful corroboration and

unnecessary excess.1 A witness may corroborate a party’s allegation as to the

color of a stoplight at the time of a collision. Another witness may offer useful

testimony to verify that account. A third, fourth, or even fifth witness has the

potential to add persuasive appeal, especially if the opposing party plans to

testify to the contrary. But how many witnesses can be put on the stand to

testify about a traffic light before belaboring the point? Ten? Twenty-five?

Where lies the threshold of sheer excess?

The Federal Rules of Evidence leave that question to the court.2 Rule

403’s cumulative evidence clause provides the trial judge with discretion to

prohibit the admission of evidence where the probative value of that evidence

is substantially outweighed by one of several risks, including the risk of

needless cumulation. The practical necessity of such a rule is readily apparent:

When the high stakes of a litigation rest in the hands of a layman jury, erring

on the side of persuasive excess will always be in a party’s interest.3 Without a

means for judicial intervention, federal courtrooms would bloat with hordes

of witnesses and piles of documents. District courts would grow mired with

needlessly long trials. Jury duty would become a full-time job, and parties

already short of patience would be further stalled from receiving redress.

But while Rule 403’s cumulative evidence clause boasts much practical

appeal, this Note interrogates its latent danger: The cumulative evidence

clause permits a court to preclude, without sound principle, the admission of

relevant evidence. Regulating prejudicial, misleading, or time-wasting risks of

trial evidence may be a job properly entrusted to the bench, but an

epistemological examination of the roles of judge and jury shows that

evaluating the purported “cumulativeness” of evidence is not. In authorizing

1. See infra Part II.B (sampling various appellate attempts to draw the line between

corroborative and cumulative evidence).

2. See FED. R. EVID. 403 (“The court may exclude relevant evidence if its probative value is

substantially outweighed by a danger of . . . needlessly presenting cumulative ev idence.”).

3. See infra Part II.A (exploring the rationale of Rule 403’s cumulative evidence clause).