ABSTRACT
T. C. Schneirla’s concept of “integrative levels” in comparative psychology (e.g., Schneirla, 1949, 1951, 1953), taken together with its major criticism that such an approach is fatally flawed in its reliance on the outmoded “Scala Natura” concept (e.g., Hodos & Campbell, 1969; see Greenberg, in press, for a useful review), has striking parallels within evolutionary theory. My goal in the present discussion is to reveal these parallels and to discuss the major criticisms of the evolutionary concept of grades (exact analogues of Schneirla’s “levels”). I will conclude that, despite serious conceptual problems, there is indeed a core empirical pattern underlying levels in comparative psychology and grades in evolutionary biology. At least insofar as evolutionary theory is concerned, the baby has been tossed out with the bathwater; something of a rapprochement is required, one which I explore at the conclusion of this discussion.
