On the nature of obsessions and compulsions.

In this chapter, we give an overview of current and historical conceptions of the nature of obsessions and compulsions. We discuss some open questions pertaining to the primacy of the affective, volitional or affective nature of obsessive-compulsive disorder. Furthermore, we add some phenomenological suggestions of our own. In particular, we point to the patients' need for absolute certainty and the lack of trust underlying this need. Building on insights from Wittgenstein, we argue that the kind of certainty the patients strive for is unattainable in principle via the acquisition of factual knowledge. Moreover, we suggest that the patients' attempts to attain certainty are counter-productive as their excessive conscious control in fact undermines the trust they need.