In this paper we present a formal way of describing plausible (or non-deductive) reasoning. Ajdukiewicz’s distinction between deductive and non-deductive reasoning [1] provides our theoretical framework. Our formal approach is given by so called operation of p-consequence, which has been described earlier e.g. in [2]. At every stage of our work we try to show that Ajdukiewicz’s framework is rel...

In this paper we apply the methodology of Labelled Deductive Systems to the tableau method in order to obtain a deductive framework for substructural logics which incorporates the facility of model generation. For this special purpose, we propose new labelled tableau calculi TL and TLe for two substructural logics L (essentially the Lambek calculus) and Le (the multiplicative fragment of intuit...