I don't know if I do - I just went and looked it up and there is so much to read I don't think I'll do it, but they probably have a lot more ideas than I do.  

The point I grasped is that of scale.  It's my very human-sized head that is doing the thinking.

I can confidently say people are not interchangeable because I don't try and have a view that is beyond the scope of my head.  Yes I know people die and get replaced and from that perspective or the 'we are all made of dust' one, you could think of people as being entirely interchangeable but it simply isn't like that for us - can you imagine trying to swop your children with the ones your neighbour has? 

I simply decided to stop bothering my head with stuff that it didn't have no truck with.  I might be intelligent but I believe so easily I'm a fool, natural fodder, I need all the help I can get just to navigate my way around all the liars and manipulators without being tripped up and, well I haven't got a good track record, tho it is going a lot better now with the wisdom of hindsight.