 Most contemporary philosophers characterize belief as a “propositional attitude”. Propositions are generally taken to be whatever it is that sentences express (see the entry on  propositions).  For example, if two sentences mean the same thing (e.g., “snow is white” in English, “Schnee ist weiss” in German), they express the same proposition, and if two sentences differ in meaning, they express different propositions. (Here we are setting aside some complications about that might arise in connection with indexicals; see the entry on  indexicals.)  A propositional attitude, then, is the mental state of having some attitude, stance, take, or opinion about a proposition or about the potential state of affairs in which that proposition is true—a mental state of the sort canonically expressible in the form “S A that P”, where S picks out the individual possessing the mental state, A picks out the attitude, and P is a sentence expressing a proposition. For example: Ahmed [the subject] hopes [the attitude] that Alpha Centauri hosts intelligent life [the proposition], or Yifeng [the subject] doubts [the attitude] that New York City will exist in four hundred years. What one person doubts or hopes, another might fear, or believe, or desire, or intend—different attitudes, all toward the same proposition. Contemporary discussions of belief are often embedded in more general discussions of the propositional attitudes; and treatments of the propositional attitudes often take belief as the first and foremost example.