Section 10.12 Inability to Perceive

• Library: Evidence 2017

H. (§10.12) Inability to Perceive

A witness may be impeached when the ability to perceive the subject matter of the witness’s testimony is at issue. When a lay witness cannot perceive the subject matter of their testimony, the witness’s competence to testify is directly at issue because the witness may not actually have personal knowledge of the subject about which the witness is testifying. See Sw. Bell Tel. Co. v. Buie, 758 S.W.2d 157 (Mo. App. E.D. 1988) (an employee lacking personal knowledge of the business’s financial records was properly barred from testifying about lost-profit damages). Admission of evidence showing the witness’s inability to perceive is one of the most commonly recognized methods of impeachment. See Mitchell v. Kardesch, 313 S.W.3d 667, 676 (Mo. banc 2010) (listing the five most commonly recognized methods of impeachment); see also §10.2, supra (discussing impeachment by introducing evidence of prior convictions, bias, prior inconsistent statements, and a witness’s character for truth or veracity). Parties are permitted to introduce extrinsic evidence to impeach a witness by showing that witness’s inability to perceive the events testified to. See State v. Allison, 326 S.W.3d 81, 92 (Mo. App. W.D. 2010).

Common sense underlies the principle of allowing impeachment on the witness’s inability to perceive because a lay witness who did not perceive the event at issue offers nothing of value to the fact-finder. Witnesses are not generally permitted to guess. Burns v. Elk River Ambulance, Inc., 55 S.W.3d 466, 482 (Mo. App. S.D. 2001); Fairbanks v. Weitzman, 13 S.W.3d 313, 318 (Mo. App. E.D. 2000). But a witness’s purported inability to perceive will most often not prevent the witness from testifying; an objection to testimony based on a witness’s perception goes to the weight, not the admissibility, of the witness’s testimony and is thus fodder for...