I'm arguing with myself:

OK. We have this character who is pragmatical, maniacal, but who thinks of himself as being solemn. Because--in his maniacalness--he views himself as being solemn, we must view his self-conceit to be ludicrous. Perhaps that's why the phrase used in the writing is 'ludicrous solemn conceit'--or his self concept is of a man who is solemn. We say to this: Balderdash!

Maybe that's it, wwh. A typo for maniacal and a character is anything but solemn.