Jubal made a fierce resolve to resign from the Philosophical Society and take up tatting.  What was "grokking"?  He had been using the word himself for a week now - and he still didn't grok it.  But what was "Man"?  A featherless biped?  God's image?  Or simply a fortuitous result of the "survival of the fittest" in a completely circular and tautological definition?  The heir of death and taxes?  The Martians seemed to have defeated death, and he had already learned that they seemed to have neither money, property, nor government in any human sense - so how could they have taxes?