W. i. thomas, a sociologist famous before world war ii, wrote, “if men define things as real, they are real in their consequences.” within which sociological perspective does this statement best fit?

The correct answer to this open question is the following.

W.I. Thomas, a sociologist famous before World War II, wrote, “If men define things as real, they are real in their consequences.” The sociological perspective that this statement best fit in is in the Structural Functionalism, specifically in the "Self-Fulfilling Prophecy," of Robert Merton.

Robert K. Merton (1910-2003) stated that the self-prophecies became true in that people believe it and that is how it happened. He developed this concept from W.I. Thomas definition of a situation quote that stated: “If men define things as real, they are real in their consequences.”  

b: the establishment clause  

b: socialism