  Abstract argumentation provides us with methods such as gradual and Dung
semantics with which to evaluate arguments after potential attacks by other
arguments. Some of these methods can take intrinsic strengths of arguments as
input, with which to modulate the effects of attacks between arguments. Coming
from abstract argumentation, these methods look only at the relations between
arguments and not at the structure of the arguments themselves. In structured
argumentation the way an argument is constructed, by chaining inference rules
starting from premises, is taken into consideration. In this paper we study
methods for assigning an argument its intrinsic strength, based on the
strengths of the premises and inference rules used to form said argument. We
first define a set of principles, which are properties that strength assigning
methods might satisfy. We then propose two such methods and analyse which
principles they satisfy. Finally, we present a generalised system for creating
novel strength assigning methods and speak to the properties of this system
regarding the proposed principles.
