Our ideas are the offspring ...

Our ideas are the offspring of our senses; we are not more able to create the form of a being we have not seen, without retrospect to one we know, than we are able to create a new sense. He whose fancy has conceived an idea of the most beautiful form must have composed it from actual existence.
 Henry Fuseli

Quotes from the same author

All actions and attitudes of children are graceful because they are the luxuriant and immediate offspring of the moment - divested of affectation and free from all pretense.
 Henry Fuseli