TRIZ: theory, method or toolbox?

While it's true that the difference between theory, method and tool is sometimes subtle, it's possible to identify which of the above categories belongs to which by referring to the practical side of its declension. So, while a theory is founded on postulates, axioms and their corollaries, a method takes the form of processes, organized or not, to serve a precise purpose. A tool, on the other hand, has a more restricted character, with a very specific mission of action in a given context. Beyond the simple Cyrillic translation of the four letters (Theory of Inventive Problem Solving), it's interesting to note that the intention of its creator (Genrich Altshuller, 1926-1998) was to call TRIZ a theory and not a method, or even a tool, as we often read