This article discusses the place of psychology in Whittaker’s circular classification of the sciences. It is shown that it was Thomas Whittaker who undertook the first attempt to build a closed circular scheme on the basis of a linear series of sciences in 1903, fifteen years before Piaget. Whittaker decomposed psychology into two independent fundamental sciences (animal psychology and human psychology) and was able to preserve psychology’s connection with philosophy, social, and natural sciences. Whittaker’s approach shows that psychology may not be a holistic science. The fruitfulness of this approach is related to the fact that considering “psychological sciences” as different disciplines we are not obliged to construct a single subject matter of psychology.