This article investigates the implications of goal-legislation for legal argumentation. In goal-regulation the legislator formulates the aims to be reached, leaving it to the norm-addressee to draft the necessary rules. On the basis of six types of hard cases, it is argued that in such a system there is hardly room for constructing a ratio legis. Legal interpretation is largely reduced to concretisation. This implies that legal argumentation tends to become highly dependent on expert (non-legal) knowledge.