The old man was a witness in a burglary trial.
The defense lawyer asks Sam, โDid you see my client commit this burglary?โ
โYes,โ said Sam, โI saw him plainly take the goods.โ
The lawyer asks Sam again, โSam, this happened at night.
Are you sure you saw my client commit this crime?โ
โYes,โ says Sam, โI saw him do it.โ
Then the lawyer asks Sam, โSam listen, you are 80 years old and your eyesight probably is bad.
Just how far can you see at night?โ
Sam says, โI can see the moon, how far is that?โ