Read the following excerpt from The Riddle of the Rosetta Stone. But the process proved to be much more difficult than de Sacy had anticipated. He succeeded in isolating the groups of demotic letters for the names of Ptolemy and Alexander, but found it impossible to identify the individual letters in the names. Eventually he gave up, saying, "The problem is too complicated, scientifically insoluble.”

Based on the details in the excerpt, the author most likely thinks de Sacy lacked

imagination.
experience.
determination.
trustworthiness.