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 one or other of these practices by referring to the practical side of their application. So, while a theory is based 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 to act 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