Social efficiency shaped much of public schooling in the United States during the early twentieth century. Simultaneously, Roman Catholic schools proliferated and became increasingly regulated by state departments of education. This led to increased influence of public education reform movements on Catholic schools. This article examines the arguments advanced by Catholic educators who questioned the educational measurement movement and eugenic-inspired reforms such as intelligence testing. It follows those debates during the early twentieth century through to the mid-century. American Catholic educators offered arguments beyond self-interest grounded in the principles of Catholic education with a commitment to educating the whole child -- mind/body-soul -- in the Thomist tradition. This historical case demonstrates how the dualist tradition of the mind/body-soul stood against the pseudo-scientific attempt of eugenicists in attempting to measure minds and bodies-souls.