Related:

• There's no use being precise about something when you don't even know what you're talking about.
  -- John von Neuma...
• There's no sense in being precise when you don't even know what you're talking about.
  -- John von Neuma...
• Do you know what you're talking about?
• Algebraic symbols are used when you do not know what you are talking about.
• Algebraic symbols are used when you do not know what you are talking about.
  -- Philippe Schnoebele...
• You don't know what you're talking about, do you?
• Algebraic symbols are used when you don't know what you're talking about.
• You wake me up early in the morning to tell me I am right?
  Please wait until I am wrong. -- John von Neumann, on being phoned at 10 a.m....
• Quote #483 "You wake me up early in the morning to tell me I am right?
  Please wait until I am wrong." -- John von Neumann [ on being phoned at 10 a.m.]...