A more thorough explanation:

A disinterested witness is someone who has no personal interest in the outcome of a lawsuit and is not affected by the case. In other words, they have no stake in the matter and are not biased towards one side or the other.

For example, if a person witnesses a car accident but has no connection to either driver or any other parties involved, they would be considered a disinterested witness. Their testimony would be considered more reliable because they have no reason to lie or distort the truth.

In contrast, if a witness has a personal interest in the case, such as being a friend or family member of one of the parties, their testimony may be viewed with suspicion. Their credibility would be questioned, and the jury would have to weigh their testimony carefully.

When evaluating the evidence presented in court, the judge should not give more weight to the testimony of a disinterested witness than to that of an interested witness. However, the judge should also not instruct the jury to disregard the testimony of an interested witness entirely. Instead, the jury should consider the specific circumstances of each witness's involvement in the case.

Overall, a disinterested witness is an important factor in determining the truth of a case. Their testimony can provide valuable insight into what happened without any bias or personal interest clouding their judgment.