It's important to note that hypothesis or theory cannot be proven, it can only be invalidated. Graphology, numerology and astrology have never been scientifically shown to be invalid. Seasoned numerologists and astrologers consistently predict fated circumstances and accurately identify personality traits.
Many times, a simple erasure of words or markings does not completely serve the requirements of an expert forger. He may make further changes to a document by replacing obliterated words or numbers with other words or numbers. A good example of this is changing the amount of a check or altering the date on a contract or will.
Even the most meticulous and gifted forgers leave behind evidence of their work. Forensic handwriting analysts visually inspect documents with the naked eye as well as with the use of a microscope. Microscopes many times disclose sure signs of forgery.