seems to me to be related to 'ripe', because in german that's "reif", which in "ausgereifte idee" has almost the same meaning and it's probably from "Reifen" ('

seems to me to be related to 'ripe', because in german that's "reif", which in "ausgereifte idee" has almost the same meaning and it's probably from "Reifen" ('tire') cognate to ring, so round or rather whole. The semantic distinction between abstract and concrete idea is still virtual, though. The ripe apple you think about is still a virtual image. Or rather original, because even scientifically in e.g. biology, specific specimen are used as arch example to define clades and such. We care very much about relational structure, after all. An abstraction thus is something loosely or not at all connected to the currently favoured theory of the overall structure of life.