Ok but I am talking about general human intelligence when I say AGI and 'recently emerged', not mollusks. You could easily argue we will find out how higher-order intelligence emerged one day, as some researchers already have models for that if you've read a college anthropology textbook; may not be right, but it's not out of the realm of possibility that it emerged recently due to new structure(s) ('design') coming about in a relatively short time period, so making the claim "Since we don't know how it happened, therefore it must be like X" is flawed.

You know what French Enlightenment thinkers were also against? Making headstrong claims (as an authority) without empirical evidence on your side :)