"Many important subjects cannot be described literally, at least not well. States of mind are like this, as are the sources and effects of language and other arts and many elements of spiritual life. They don't just require pictures in order to be understood. They require comparisons, because they cannot be depicted literally in images or in words. A subject tends to defeat literal description when it is inaccessible to the senses; our words for what we can see are more extensive and refined than our words for what is intangible. Other truths and observations cannot be captured through a literal use of words simply because words and reality aren't coextensive. The range and subtlety of feeling of what we wish to say outruns the labels that our language provides for the purpose. Comparisons free us from those limits. They allow a writer to use words not as labels to name a thing but as links to attach it to what we have known or seen or can imagine. The link summons pictures and other associations in the reader's mind and rallies them to the descriptive purpose. A metaphor may, in short, express something that otherwise cannot be said or shown, and provide a way to understand it — possibly the only way. [emphasis added]"