How we cite our quotes: All quotations are from Young Frankenstein.
Quote #1
FREDERICK: My grandfather was a very sick man.
Here, Frederick is using sick to mean "crazy" or "mad," and it shows us two things. He thinks his grandfather was mentally ill, and instead of being sympathetic toward it, he thinks his grandfather deserves to be discredited.
Quote #2
FREDERICK: You are talking about the nonsensical ravings of a lunatic mind.
Speaking of discrediting his grandfather's accomplishments, here we see just that. Even though his grandfather was a brilliant scientist in some respects, Frederick believes all his work should be null and void. Personally, Shmoop thinks that Mel Brooks, in writing this line, was gleefully referring to himself and his screenplay.
Quote #3
VICTOR (as read by FREDERICK): Until in the midst of this darkness, a sudden light broke in upon me. A light so brilliant and wondrous and yet so simple. Change the poles from plus to minus and from minus to plus. I alone succeeded in discovering the secret of bestowing life. Nay, even more I myself became capable of bestowing animation upon lifeless matter!
Here's Victor Frankenstein writing in his journal about the secret to success—reverse the polarity. Besides being a horror movie trope, this description shows that sometimes delusions appear to the insane person as a flash of insight. Grandpa Victor's got a serious case of delusions of grandeur, wouldn't you say?