Abstract

The first part of the paper characterises two new non-extensional functors: functor of counterfactual implication and functor of causal implication. The latter functor was used by Arthur W. Burks in his early considerations on the construction of a system of the logic of causal propositions, the formal inscription of conditional propositions in the colloquial language and the language of empirical sciences. The second part traces down the mutual relations between the functors of counterfactual implication, causal implication, material implication and strict implication. Special attention is paid to the fact that causal implication implies material implication (a converse relationship does not occur), and strict implication implies causal implication (a converse relationship does not occur)