KDD (Knowledge Discovery in Databases) confronts us withphenomena that can intuitively be grasped as highly problematic, but arenevertheless difficult to understand and articulate. Many of theseproblems have to do with what I call the ``deindividualization of theperson'': a tendency of judging and treating persons on the basis ofgroup characteristics instead of on their own individual characteristicsand merits. This tendency will be one of the consequences of theproduction and use of group profiles with the help of KDD. Currentprivacy law and regulations, as well as current ethical theoryconcerning privacy, start from too narrow a definition of ``personaldata'' to capture these problems. In this paper, I introduce the notionof ``categorical privacy'' as a starting point for a possible remedy forthe failures of the current conceptions of privacy. I discuss some waysin which the problems relating to group profiles definitely cannot besolved and I suggest a possible way out of these problems. Finally, Isuggest that it may take us a step forward if we would begin to questionthe predominance of privacy norms in the social debate on informationtechnologies and if we would be prepared to introduce normativeprinciples other than privacy rules for the assessment of newinformation technologies. If we do not succeed in articulating theproblems relating to KDD clearly, one day we may find ourselves in asituation where KDD appears to have undermined the methodic andnormative individualism which pervades the mainstream of morality andmoral theory.