David

Both show a high degree of self awareness and desire to communicate, inform, etc. so why such a long time to go from painting to writing and please don't say early writing was a form of graphic description e.g. hieroglyphics. Also don't mention trading as the motivation, that's way to simplistic unless you are suggesting that the earth was populated by lonely painters who never formed a group or tribe until they wanted to trade (how did they survive before with their paints and a spear).

I really want to know a plausible theory; if you think about it it's way to long a time according to conventional 'wisdom'? Leave any religious beliefs out of your reasoning please.