Can we think about leadership not first from "what it is", assuming there is "a thing called leadership" as our starting point,
but instead from "what do we think this 'leadership' thing is supposed to do?"
That is, what are the functions or impacts of a thing we might call leadership? How do we think it would work? What are the theories of change about the impact that our behaviours might have (that reflect what we might call leadership)?
This way, we might not be able to be clear what leadership "is or is not", but we can at least make solid, verifiable claims about things that happen in the world (patterns of personal influence), thus informing how we can behave in order to more effectively realise our intent in communion with others.