Abstract
In the chapter “Information and Content” of their Impossible Worlds, Berto and Jago
provide us with a semantic account of information in deductive reasoning such that
we have an explanation for why some, but not all, logical deductions are informative.
The framework Berto and Jago choose to make sense of the above-mentioned idea is a
semantic interpretation of Sequent Calculus rules of inference for classical logic. I shall
argue that although Berto and Jago’s idea and framework are hopeful, their definitions
do not capture what is intended. This is so because the definitions are solely based on
the logical complexity of an argument and they fail to capture the richness of the non-
logical content of that argument. Then I will suggest some amendments to address this
problem. Finally, I will extend the application of the definitions to first-order logic. It
shall be observed that in some classical deductions, applying contraction may lead to
hiding some epistemic impossibilities. This happens when formulae which contribute
different propositions to the proof get contracted at the quantified level.