The reading passage explore the origin of the Voynich manuscript. The professor's lecture deals with the same issue. However, his ideas contradict with three theories mentioned in the reading.
Firstly, even though the reading passage indicates that the manuscript is a genuine work on some scientific or magical subject composed in a complex secret code probably by Anthony Ascham, a sixteenth-century physician and botanist. The professor argues that Anthony Ascham’s book - A Little Herbal contains common plants which are well-known.Thus they have no need to be written as secret document. 
Secondly, the reading claims that the manuscript is really a fake and its text has no real meaning, they are produced by Edward Kelley, to get profits from rich person. However, the professor contends that the manuscript is careful about using the real code. The wealthy noble at that century is easy to fool so that Edward Kelley didn't have to make it too complex to pursuit his purpose. 
Thirdly, the reading indicates the manuscript is actually a modern fake created by Wilfrid M. Voynich himself, while the lecture asserts although Voynich can get the vellum, he cannot get the old manuscripts' inch to create the fake manuscript. Obviously, the professor's argument disproves its counterpart in the reading.