Rule 602: Need for Personal Knowledge

Rule 602 requires that a lay witness (non-expert) can only testify about things they personally perceived through their own senses — what they saw, heard, smelled, touched, or otherwise directly experienced. A witness cannot testify about events they only learned about secondhand or about matters they have no direct knowledge of.

The personal knowledge requirement works as a foundation for testimony. Before a witness testifies about a fact, there must be enough evidence to support a finding that the witness actually knows about that fact from personal experience. The witness's own testimony can supply this foundation — for example, 'I was standing at the corner when the accident happened, and I saw the car run the red light.'

This rule does not apply to expert witnesses testifying under Rules 702-705, because experts are specifically allowed to base their opinions on information they did not personally observe, as long as it is the type of information experts in the field would reasonably rely upon. The personal knowledge requirement also overlaps with but is distinct from the hearsay rule — both aim to ensure that testimony is based on reliable firsthand information.