In his “Vorlesungen über die Menschen und Tierseele” (cf. 2nd ed., p. 370), Wundt proclaims his rupture with the impressionistic school in the following terms: “The one great defect of this popular psychology is that it does not take mental processes for what they show themselves to be to a direct and unprejudiced view, but imports into them the reflections of the observer about them. The necessary consequence for animal psychology is that the mental actions of animals, from the lowest to the highest, are interpreted as acts of the understanding. If any vital manifestation of the organism is capable of possible derivation from a series of reflections and inferences, that is taken as sufficient proof that these reflections and inferences actually led up to it. And, indeed, in the absence of a careful analysis of our subjective perceptions we can hardly avoid this conclusion. Logical reflection is the logical process most familiar to us, because we discover its presence when we think about any object whatsoever. So that for popular psychology mental life in general is dissolved in the medium of logical reflection. The question whether there are not perhaps other mental processes of a simpler nature is not asked at all, for the one reason that whenever self-observation is required, it discovers this reflective process in the human consciousness. The same idea is applied to feelings, impulses, and voluntary actions which are regarded, if not as acts of intelligence, still as effective states which belong to the intellectual sphere. “This mistake, then, springs from ignorance of exact psychological methods. It is unfortunately rendered worse by the inclination of animal psychologists to see the intellectual achievements of animals in the most brilliant light.... Unbridled by scientific criticism the imagination of the observer ascribes phænomena in perfectly good faith to motives which are entirely of its own invention. The facts reported may be wholly true; the interpretation of the psychologist, innocently woven in with his account of them, puts them from first to last in a totally wrong light. You will find a proof of this on nearly every page of the works on animal psychology.” (English Translation by Creighton & Titchener, p. 341.)