  In abstract argumentation theory, many argumentation semantics have been
proposed for evaluating argumentation frameworks. This paper is based on the
following research question: Which semantics corresponds well to what humans
consider a rational judgment on the acceptability of arguments? There are two
systematic ways to approach this research question: A normative perspective is
provided by the principle-based approach, in which semantics are evaluated
based on their satisfaction of various normatively desirable principles. A
descriptive perspective is provided by the empirical approach, in which
cognitive studies are conducted to determine which semantics best predicts
human judgments about arguments. In this paper, we combine both approaches to
motivate a new argumentation semantics called SCF2. For this purpose, we
introduce and motivate two new principles and show that no semantics from the
literature satisfies both of them. We define SCF2 and prove that it satisfies
both new principles. Furthermore, we discuss findings of a recent empirical
cognitive study that provide additional support to SCF2.
