premise: William Irving Turner (1890–1950), commonly known as Tim Turner or W.I. Turner, was an American architect. He served as a U.S. Forest Service architect and is credited with much of the design of Timberline Lodge on Mount Hood in Oregon, an important and influential work.
hypothesis: Tim Turner was not the only one who contributed the design of the Timberline Lodge.
reason: This is "definitely correct" based on the information given since Turner is only credited with "much of the design" not all of the design of the Timberline Lodge. So, there must of been at least one other individual or contributor to the design. 