If the most useful rule of evidence is Rule 104, by far my favorite is the beautiful Rule 602. The first sentence says, “A witness may testify to a matter only if evidence is introduced sufficient to support a finding that the witness has personal knowledge of the matter.” This is in both the Texas and federal rules.
Begin with the thought of the tower with five windows. Each window lets in light. Each is a stained-glass window and the light coming in is a different color from each other. These windows represent the five senses. A witness may only testify to a matter if evidence is sufficient to support a finding that he has seen the light of one of these windows.
It is not good enough that someone told him about the windows; he must have seen it with his own eyes. It is not good enough that he dreamed about it, or read it on the internet, or saw it in a you-tube video.
This is a quote I like: “The witness’s testimony must be based on events perceived by the witness through one of the five senses.” 3 Weinstein’s Federal Evidence 2d, ¶602.02.
If the experience was not seen or smelled or felt or tasted or heard, it was not perceived by the witness.
The witness does not have to testify that he is certain of the memory or that he gave perfect attention to the observation. MCCORMICK ON EVIDENCE § 10 (8th ed.). So, the witness may say, “I think” or “I believe,” but the statement still must refer to something perceived through the senses.
We do have personal knowledge of our own age and date of birth. WRIGHT AND MILLER ET AL., FEDERAL PRACTICE AND PROCEDURE, Evidence § 6026 (2d ed.). I would suggest this is still consistent with knowledge gained through what the senses have perceived. I have little recollection of what happened before the age of three. Nor have I counted each of the 72 birthdays. But my senses perceived many changes from growing to voice changes to balding, weight gain, aging and shrinking in stature. I have some certainty about my age gathered through the senses. And so do we all.
This rule brings us back to the ever-important Rule 104. A court should exclude testimony only when a reasonable jury would have to conclude that the witness did not perceive the matter in question. “Rule 602 clearly places on the proponent of the testimony the initial burden of showing that it represents the witness’ personal knowledge. This is the general common law rule. See, e.g., 2 Wigmore, Evidence § 654 at 883 (Chadbourn Rev. 1979); McCormick, Evidence § 10 at 24 (3d ed. 1984).” United States v. Davis, 792 F.2d 1299, 1304 (5th Cir. 1986).
Rule 602 arises in every trial. It is usually accompanied by Rule 402, relevance, Rule 802, hearsay, Rule 403, prejudice, and the right of the accused to confront the witnesses against him. These are among my next favorite rules and we will discuss them further, later.
In the meantime, I will try to commit to memory the phrase, “only if evidence is introduced sufficient to support a finding that the witness has personal knowledge…” I urge my colleagues to do the same.