X, a Chemistry student at Gauteng University, struggled financially. He therefore decided to manufacture a psychoactive drug to stimulate the central nervous system, which causes a longer concentration span. Students were of course the majority of his customers! Within a month of starting his business, X was arrested and charged with drug dealing. The Drug Prevention Act of 2013 prohibits the sale of substances containing opium, olium, norium and other toxic materials. The presiding judge held that, since the Act does not specifically mention drugs with psychoactive effect, he would use the definition clause of the legislation to determine whether X's drug fell under "toxic materials". What theory of interpretation did the judge use in this instance? In your answer, also indicate whether or not X would have been found guilty of an offense.