But once we get past these sorts of "self-referential" propositions, propositions whose very subject matter encompasses the fact that they are believed, it is hard to come up with uncontroversial examples of infallible beliefs.
Elementary propositions are propositions whose truth depends entirely on the presence of an atomic fact, and other propositions have a determinate and unique analysis in which they can be construed as built up from elementary propositions in truth-functional ways.
A balding, bespectacled former mathematician who applied his skills to casino tables and then to private money management, he publishes something called Perfect 10, a quarterly nudie magazine whose selling proposition is that the women in it aren't surgically enhanced.
So let analytic propositions be those framework propositions whose negations are self-contradictory.
Reichenbach objects that some quantum mechanical propositions whose logical form contains no propositional operators may be unverifiable.
He avoids the second assumption by presupposing the existence of an "ethically neutral" proposition (a proposition whose truth or falsity does not affect the agent's utilities) which the agent takes to be just as likely to be true as she takes it to be false.
Let's call the class of propositions whose evidence is restricted to those who first believe "restricted propositions".
And certain propositions whose truth values can change over time (propositional fluents) are also treated as individuals.
Kant's instruction to ask ourselves of a maxim whether we can will without contradicting ourselves that it should become a universal law is of no use, according to Bolzano, since for him there is no practical proposition or ought proposition whose contradictory opposite is self-contradictory.
