Deontic logic for lawyers Concepts without formalism

Deontic logic is the logic of what ought to be done, or what ought to be the case. In this paper, I attempt to bring deontic logic closer to the interests of theoretically interested lawyers. To that end, I use examples of deontic reasoning that, although simplified for expository purposes, resemble real legal arguments. Moreover, I refrain from formalisation. It is possible to distinguish three ‘steps’ of deontic reasoning, and these three steps structure the argument of this paper. The first step is from non-deontic facts to the duties (or obligations) an agent has. The second step is from duties to what an agent (legally) ought to do. And the third step is from what an agent ought to do to whether an act performed by the agent was lawful or not. Deontic logic is a broad subject, and I had to be selective in the topics that are addressed. The selected topics are the structure of ought-to-do facts (section 2); norms, duties, obligations and what an agent ought to do (section 3); reasoning with norms (section 4); deontic inheritance (section 5); and three kinds of permission (section 6). The conclusion of the paper lists differences between other treatments of deontic logic and the present approach.