> But trying to strictly define this - which is necessary before we can meaningfully talk about it - ... It is difficult to formally define, but it is not nece

> But trying to strictly define this - which is necessary before we can meaningfully talk about it - ... It is difficult to formally define, but it is not necessary to have such a definition to meaningfully talk about it. This is quite general - many concepts do not have formal definition and certainly not all can have one - formal definition only works well when its expanded form has root in concepts that require no formal definition. "really happening", like "matter" are intuitive concepts that refer to experience, do not have formal definition and so cannot be further reduced.