As evidenced by all of the fossils, remains, anthropological evidence, and history that has been discovered and documented on life’s existence (amino acids to modern primates and what lysergic acid diethylamide could enlighten us to), there is ample evidence we have had a long path of evolution that gets me/us to the point I can articulate this.
HOWEVER, the nature of this post is a thought exercise that goes beyond this. What if we have been here before. What if a life’s evolutionary path had already been followed (maybe multiple times) and by design (or coincidentally) evidence of its existence had been obscured and/or literally wiped out.
Let’s say that a society did evolve and by (eventual?) design and adhered to the rule “make everything abide by ecologically adhered to principles”. A society could have evolved, and if it truly DID abide by such (see post “Genes to Beans (building on Cradle to Grave)”), no remains SHOULD exist and NO evidence of it could/might be found.
(see ISO 14000/14001/etc. on standards for environmental behavior)
Past civilizations/cultures could have mandated themselves to decompose everything regarding their existence such that we would never know they were here.