 Whether a statement is a “proposition” or a “presupposition” is determined not by its content but by the role that the statement plays in the logic of question and answer. If its role is to answer a question, then it is a proposition and it has a truth-value. If its role is to give rise to a question, then it is a presupposition and it does not have a truth-value. Some statements can play different roles. They may be both propositional answers to questions and presuppositions which give rise to questions. For example, that an object is for something, that it has a function may be a presupposition which gives rise to the question “what is that thing for?”, but it may also be an answer to a question if the statement has the role of an assertion. Philosophical analysis is concerned with a special kind of presupposition, one which has only one role in the logic of question and answer, namely that of giving rise to questions. Collingwood calls these presuppositions “absolute”. Absolute presuppositions are foundational assumptions that enable certain lines of questioning but are not themselves open to scrutiny. The three senses of causation discussed above are examples of absolute presuppositions which structure different forms of inquiry. A physician, for example, absolutely presupposes sense II of causation, according which a cause is