The secret as a form is seen by Simmel as central in social interaction. Knowing about each other is essential for social living. Yet all human interaction is also accompanied by a withholding of information. Sharing fully with others one's inner-flow of consciousness is impossible, and selection also provides scope for purposefulness. Sincere self-disclosure and its opposite only come about in the context of a wider, ever-present, "not knowing" about one another.