How do professional futurists contend with prognostic uncertainty? There is an impressive body of medical-sociological research on how medical staff deals with uncertainty. We have used these insights to study patterns and manners in foresight practice that might not be evident otherwise. The question "Do professional futurists use approaches to deal with uncertainty that resemble those of medical staff?" is addressed by ongoing ethnographic research in Dutch foresight practice. The observed manners are grouped into four analytic categories: the construction of solidity, numeric discourse, communication habits and experience as anchor. In this paper, the construction of solidity and experience as anchor are described in detail. It is further more suggested that "certainification" is a possible upshot of these manners in use.