 One of the first frontal attacks on the concept of instinct was that of social psychologist Knight Dunlap (1919). He contrasted two general approaches to the study of instinct. The “physiological” approach identified each instinct with a distinct neuro-physiological mechanism. Dunlap was in principle supportive of this approach, claiming that it could potentially generate useful definitions of particular instincts. However, Dunlap lamented that, “I am very strongly convinced that it is not at present possible to secure agreement to confine the term to this meaning” (1919, 308). The problem, he thought, stemmed from the prevalence of “teleological” approaches to instinct, of which McDougall was a prime example. On the teleological approach, components of behavior are grouped together as members of a class according to their tendency to generate some functional outcome. Dunlap cited the “moral instinct” and “the instinct for pugnacity” as examples. Dunlap was willing to tolerate this approach provided that “[t]he grouping of activities into ‘instincts’ [is] … clearly understood to be a device of convenience only, similar to the arrangement of documents in a well ordered filing system” (1919, 309). Problems emerge, he thought, when psychologists reified those groupings, regarding them as natural (as opposed to instrumental) categories. Dunlap argued that this tendency encouraged psychologists to draw faulty inferences. For example, “Having posited a ‘pugnacious instinct,’ … one writer proceeds gravely to infer that war is forever a necessity, as the expression of this instinct.” (Dunlap 1919, 309). From identifying pugnacity as a natural teleological category, psychologists inferred that it is developmentally fixed. Dunlap recognized that this inference was empirically unwarranted.