Conjecturing from consequences

This paper deals with a more general way of defining conjectures than that presented in Trillas et al. Here conjectures are defined once an operator of consequences in the sense of Tarski is given, and like in Trillas et al. they result classified in consequences, hypotheses and speculations. With all that, it appears for the first time the actually non-surprising idea that a formalization of deduction seems to be required previously to formalize induction and abduction.