 In the case of dialectical and demonstrative methods, the aim is to reach either agreement on the facts, or certainty about the facts. In both these cases the rules must include rules of inference, like the rules of syllogism which Aristotle codified in Prior Analytics. But all the methods, even the non-inferential ones, must also have rules about what to adopt as starting premises. In the case of rhetoric, practicality implies that the orator should choose premises that the audience will accept; likewise in dialectics it makes sense to start with premises that have some plausibility. Al-Fārābī believes that in practice the community will insist on restrictions that add a note of objectivity: for example, that experts agree to the premise, or that nobody positively disagrees with it. He formulates some conditions along these lines, including that the premises must be at least “standard” (masshūr) or “received” (maqbūl). (For discussion of such conditions and where they apply, see Aouad 1992 and Black 1990: Chapter 5A.)