Quote from : Invasion of the Body Snatchers Movie

Jack Belicec: Stop trying to rationalize everything, will ya? Let's face it, we have a mystery on our hands!
Dr. Dan 'Danny' Kauffman: Sure you have. A real one! Whose body was it, and where is it now? A completely normal mystery. Whatever it is, it's well within the bounds of human experience, and I don't think you ought to make any more of it.
Dr. Miles J. Bennell: Look, I wouldn't if I hadn't looked in Becky's cellar! How do you explain away the body I saw there?
Dr. Dan 'Danny' Kauffman: I don't think you saw one there.
Dr. Miles J. Bennell: You don't think I saw one here, either?
Dr. Dan 'Danny' Kauffman: I know you did because three others saw it too.
Dr. Miles J. Bennell: But I dreamed up the second one?
Dr. Dan 'Danny' Kauffman: Doctors can have hallucinations too.