Emotions, my dear Seldon, are a powerful engine of human action, far more powerful than human beings themselves realize, and you cannot know how much… - Isaac Asimov

Were I to use the wits the good Spirits gave me,” he said, “then I would say this lady can not exist - for what sane man would hold a dream to be reality. Yet rather would I not be sane and lend belief to charmed, enchanted eyes.

Connotations and associations; the subtle effect, not of dictionary meaning, but of years of usage; the nature of the sentences and conditions and events in which one has experienced the use of one word as compared with that of the other.

If a modified robot were to drop a heavy weight upon a
human being, he would not be breaking the First Law, if he did so with the knowledge
that his strength and reaction speed would be sufficient to snatch the weight away before
it struck the man. However once the weight left his fingers, he would be no longer the
active medium. Only the blind force of gravity would be that. The robot could then
change his mind and merely by inaction, allow the weight to strike. The modified First
Law allows that" (79).