 There are many different platonistic conceptions of propositions. For instance, Frege (1892, 1919) held that propositions are composed of senses of words (e.g., on this view, the proposition that snow is white is composed of the senses of ‘snow’ and ‘is white’), whereas Russell at one point (1905, 1910–11) held that propositions are composed of properties, relations, and objects (e.g., on this view, the proposition that Mars is red is composed of Mars (the planet itself) and the property of redness). Others hold that propositions do not have significant internal structure. The differences between these views will not matter for our purposes. For more detail, see the entry on  propositions.