ambulatory discernment machine and facile breeding apparatus that is the human animal , more efficient than ancient floral species ever evolved to do , succumbs easily from his menial exertions to sleep ; and what is sleep : the demolition of the day , with debris bulldozed into a landfill , so that a new day can be built upon the very spot , thus 20,000 troys on 20,000 strata of the selfno 20,000 selves , and each barely remembering its immediate successor let alone its distant ancestors .