The consequence of these features is that a mathematical text is generally not understandable without some prerequisite knowledge.
H. B. Williams, an electrophysiologist, wrote in 1927: Now mathematics is both a body of truth and a special language, a language more carefully defined and more highly abstracted than our ordinary medium of thought and expression.
Also it differs from ordinary languages in this important particular: it is subject to rules of manipulation.
Now this comes very close to what we conceive the action of the brain structures to be in performing intellectual acts with the symbols of ordinary language.
In a sense, therefore, the mathematician has been able to perfect a device through which a part of the labor of logical thought is carried on outside the central nervous system with only that supervision which is requisite to manipulate the symbols in accordance with the rules.