Specific, definite, concrete Prefer the specific to the general, the definite to the vague, the concrete to the abstract. William Strunk Jr. & E.B. White, The Elements of Style examples
Student's future, not teacher's past Teachers should prepare the student for the student’s future, not for the teacher’s past. Richard Hamming, The Art of Doing Science and Engineering: Learning to Learn Ambitions for someone else's mind teaching