§ 2602 Personal knowledge.

If someone wants to testify about something in court, they need to actually know about it firsthand. This means they saw it, heard it, or experienced it themselves. A witness can't just guess, assume, or repeat something they heard from someone else and call it their own knowledge.

To prove they have this firsthand knowledge, the witness can simply say so in their own testimony. For example, a witness can state that they were present at the scene or that they personally saw an event happen. That statement alone can be enough to show they have the personal knowledge needed to testify about it.

There is one exception to this rule. Expert witnesses follow different rules under Section 2703. Experts are often allowed to give opinions based on their training and experience, even if they did not personally witness the事件 in question.