 Ernest Adams wrote two papers (1965, 1966), and later a book (1975) developing a logic for conditionals assessed as conditional probabilities. Like Ramsey, he was sceptical of the idea of conditionals as propositions with truth conditions, and developed a logic based on probability. He showed that valid arguments have an interesting probability-preserving property: the uncertainty (i.e. 1 − the probability) of the conclusion cannot exceed the sum of the uncertainties of the premises. He applied this criterion to arguments with conditionals, and an interesting logic emerged. The paradoxes of material implication are invalid. Specifically, with material implication, \(\neg A\) guarantees the truth of \(A \to B\). But here, the probability of \(\neg A\) can be high while the probability of \(B\) given \(A\) is low.  (\(B\) given \(A\) is the analog of \(A \to B\).) More surprisingly, there are counterexamples to transitivity, contraposition, and strengthening of the antecedent (see Section 3.2 of the entry on   indicative conditionals,  for examples and more details).