 Though these ideas are coextensive, we can still distinguish them by noting that they have different parts, e.g., that [prime] occurs in the first, but not in the second. Bolzano will say in such cases that the content of the two ideas is different. According to his definition, the content of a complex idea is the sum of its parts. ‘Sum’ is a technical term in Bolzano’s ontology, designating collections “in which the manner of combination does not matter and in which the parts of the parts may be considered parts of the whole” (TS, §84). For our purposes, it is sufficient to note that when Bolzano asks us to think about the content of an idea, he wants us to consider its parts, but not their arrangement.