Good points, even that from Heinlein.
To determine humans as the "noblest" entity on earth is a subjective matter on someone own.
And I appreciate your take about protein utilization of our organs, cff.
I end my part of discussion here, because it's too critical. I could come with various points to defend my credibility in this discussion, but I'm too tired.
One thing is to say: with our kind of nourishment, our dentures for example were degenerated after a long span of time and we are mostly dependented on our technology to survive. We need to be doctrinated during our infant lifetime, without - we wouldn't be capable to life.
My only point was, human existance is relative significant.
And yes, I never really contradict the case of the farmer's self-defend.
Yes mankind did much. He procreate himself on a great level, built big cities and changed the global climate, failed to comprehent matter though using nuclear weapons and so on. That's no point or provocation, only wellknown superficial facts, which should make everybody thoughtfully about claims of the own species for superiority and importantance.
Damn, now I'm posing like a hippie