argued that the section used the words "adult person" not as a technical legal word (because the technical words are words such as "majority" or "full age") but rather simply to refer to the common meaning of who is an adult. Thus section 41 entitled King to vote, because the meaning of "adult person" in South Australia was a person over 18. Murphy attempted to call evidence from a professor of sociology to support the claim that persons over 18 were considered mature persons in Australia. However, Chief Justice Barwick said that the court would only consider that evidence if they found that the meaning of "adult person" in section 41 was uncertain. Nature of section 41 An alternative argument raised for the respondent Jones was that section 41 was only ever intended to be a transitional provision, to have effect only until the Parliament of Australia made laws about who could vote in federal elections. On this view, the section could be read as referring only to adult persons who were alive when the Constitution came into effect, or referring only to state laws in force when the Constitution came into effect, under which people might acquire a right to vote. This argument was first raised by John Quick and Robert Garran in their 1901 book, The Annotated Constitution of the Australian Commonwealth. Jones argued that this interpretation should be adopted because of section 30 of the Constitution. That section provides that "Until the Parliament otherwise provides", the eligibility of people to vote at a federal level would be determined by state laws. The argument was that similarly, section 41 was a transitional provision designed to preserve the status quo until the parliament made laws about the subject (the first such law being the Commonwealth Franchise Act 1902). Judgment In a unanimous decision, the court held that the words "adult person" in section 41 were fixed with the meaning they had when the Constitution came into effect, and thus applied only to people aged over 21. Justice Stephen summed up the court's opinion: "The ordinary legal meaning of "adult"... was, at Federation, and had for centuries been, that of a person who had ceased to be an infant and had attained full age by attaining the age of twenty-one years." Because the court decided that King was not an "adult person", and that section 41 did not apply to