The man who knows governments most completely is he who troubles himself least about a definition which shall give their essence.
 William James, The Varieties of Religious Experience (1902). copy citation

Context

“for example, one man might tell us it was authority, another submission, another police, another an army, another an assembly, another a system of laws; yet all the while it would be true that no concrete government can exist without all these things, one of which is more important at one moment and others at another. The man who knows governments most completely is he who troubles himself least about a definition which shall give their essence. Enjoying an intimate acquaintance with all their particularities [pg 027] in turn, he would naturally regard an abstract conception in which these were unified as a thing more misleading than enlightening.” source