The old man was a witness in a burglary trial.

The defense lawyer asks him, "Did you see my client commit this burglary?"

"Yes," says the old man, "I saw him plainly take the goods."

The lawyer asks him again, "This happened at night; are you sure you saw my client commit this crime?"

"Yes," says the old man, "I saw him do it."

Then the lawyer asks him, "Listen, you are 80 years old and your eyesight is probably bad. Just how far can you see at night?"

The old man says, "I can see the moon; how far is that?"