David Bourland introduced E-Prime with the goal of avoiding imprecise language (Bourland 1965).   E-Prime encourages a less absolute style of writing that reduces the possibility for misunderstanding and conflict.   A key insight of E-Prime is that use of the word “is” often leads to imprecise language that can lead to needless conflict.

Consider the following parable.  Abe tells Bob that,  “Tom is grouchy.”   Bob tells Abe that, “You are wrong, Tom is cheerful.”  From this point Abe and Bob could get upset and call each other liars.  If however they continued to explore their seeming contradiction, they would notice that Abe always sees Tom in the mornings, and Bob always sees Tom in the evenings.  Tom is not a morning person.   They could have spoken more precisely. 

When using E-Prime, one is careful with the word “is” and recognizes the limits of scope for what can be claimed.  Here, at least two factors limit scope, the time and the observer.  Being careful, Abe might say, “Tom seems grouchy to me when I see him, which is usually about 9:00AM, most mornings.” Likewise, Bob might say, “Tom seems cheerful to me when I see him in the evenings.”