Sunday on the Front Stoop, Why are we here?

Why are we here?  This question has echoed down (up?) the ages from the beginning of human communication through language.  The Greek philosophers were not the first to consider the reason for human existence.  Records of previous conversations on this subject are long lost and if they were recorded on surfaces they have erroded away or been the victims of the distructions of war or natural forces.  But we can safely say that as soon as humans could communicate complex thoughts to each other (and this is our truly unique gift as a species) the subject of why we are here came up.  So lets talk it over some more.  And maybe move understanding just a little further down (up?) the road.