Yet don't you think your last statement there is a perfect example of walking through a quiet wood and declaring a woodpecker absent? We certainly don't understand non-human languages/communication systems, and significant evidence is piling up that it's often far more sophisticated than we think it is. And "building on previous generations' achievements" is a little ill-defined; isolated groups of individuals often form a unique society, even if they aren't conducting research on human intelligence.
I didn't say other species clearly do not possess equally impressive linguistic abilities. But qualitatively, our stand in sharp distinction. Surely, we can never be certain the woodpecker is absent, but, that's just a new take on the fact that our theories are merely the expectations with maximum probability. I stay open, and prepared to accept if a new sign of legacy-based behaviour is found in other species, as well as a form of extra-neural storage of symbolic configurations (e.g writing). But surely you cannot ask me to expect those.
I'm not sure about what you meant in your last remark. I meant that humans are uniquely able of starting where the former generations left off. This explains the techno-ideological development that has been occurring naturally for all and any of us (unless a library was burned down, which was a pathological thing to do).
