The Tacit Dimension

Thirty years after its appearance, Blankenburg's "Psychopathology of common sense" has not lost its relevance. In my commentary I will try to illustrate the fruitfulness of his approach by pointing to some connections with the phenomenology of the body as well as with recent memory and infant research.

As Blankenburg himself indicates, the notion of common sense developed by a shift of meaning from the classical sensus communis and thus has its original basis in the sensual-bodily experience. By the koinè aísthesis, Aristoteles meant a central sense organ integrating all single modalities of sensation (which he localized in the heart). In German physiology and psychiatry of the nineteenth century, the sensus communis was still translated as "Gemeingefühl" ("common feeling") or "cenesthesia" (Fuchs 1995). This term denoted the inner, proprioceptive bodily sensations, but also an original unity of the senses, which has been rediscovered by recent infant research as intermodal sensory perception. The affection of the body was thus regarded as the common basis of all sensation.

Looking on this track for a bodily basis of the common sense, we find it in the habitual structure of the lived-body as analysed by Merleau-Ponty (1945). The body is the primary "matter-of-course," namely, the tacitly functioning medium of our everyday being-in-the-world prior to any subject-object split. The body schema, in Merleau-Ponty's view, is not only a system of familiar units of movement or "kinetic melodies," it also incorporates the surrounding things, tools, and spaces that are familiar to us and that we "inhabit." Thus, the musician "does not only manipulate the instrument like a separate object, but lives in it like a limb and inhabits the expressive musical space it opens" (Behnke 1997). But for Merleau-Ponty, the body schema is also the basis of "intercorporeity," i.e., a prepersonal sphere of reciprocal comportment and understanding prior to any explicit consensus and symbolic communication. In this sphere of elementary contact, the "atmospheric" senses play a major role: The sense of smell (as shown, e.g., by the expression "to scent treason" or in German, "jemand nicht riechen können" [not be able to "smell" or stand someone]) as well as the sense of taste whose ambiguous meaning, mentioned by Blankenburg, points to the bodily basis of the feeling for what is suitable, decent, or aesthetically pleasing. Even the designation of homo sapiens that we give to ourselves is derived from the latin sapere (to taste/to know), and thus shows that the knowledge characteristic for man is not an explicit one, but an intuitive, implicit knowing or "feel" for his surroundings, or as Kant says, an "aesthetic rather than intellectual judgment" (cited by Blankenburg).

Polanyi (1967) has analysed this knowledge at the roots of common sense as "tacit knowledge." It is based on processes of Gestalt formation that enable us to grasp unified wholes through their constituting elements without still being aware of the latter. Thus, we understand the facial expression of others immediately but cannot tell from which details. Or we know how to waltz without knowing the single movements or being able to explain it. Tacit knowledge implies all the taken-for-granted that we have forgotten once it has become our second nature and part of our bodily habits. It is mainly based on the neuronal coupling of single sensori-motor units by repeated perception or action. This unconscious knowing has only recently come to be explored by psychology under the heading of "implicit" or "procedural memory" (Schacter 1987, 1996). It contains familiar styles or "melodies" of moving, perceiving, and being-with-others in which our whole bodily and emotional experience is engaged. There is an atmospheric, "felt" quality about them that cannot be analysed into single elements. Implicit knowledge may, therefore, never be wholly expressed by words—it is only realized in the concrete situation. It may only be circumscribed by expressions such as "how it feels...," "how it is...," e.g., how it is...