chapter 16 broaching the personal if , when conflated with sensory input , emotion is that which is the genesis of thought and intelligence , adulterating emotion adulterates both ; and if the impressions of personal experience are not to be trusted as a form of truth , then no individual has anything whatsoever to offer to posterity ; and without the ability to reach posterity an evanescent life will have been proven with enough time by whatever comes thereafter with time to have never existed , although , to himself , contentment and satisfaction in such a petty life is possible if consistency over the years in job , friends , and family , that which is perennial to a mans brevity on the planet , is maintained .