There is hardly any person living concerning some essential part of whose character there are not differences of opinion even among his intimate acquaintances
 John Stuart Mill, A System Of Logic, Ratiocinative And Inductive (1843). copy citation

Context

“But if it be impossible to ascertain the influencing circumstances with any approach to completeness even when we have the shaping of them ourselves, much more impossible is it when the cases are further removed from our observation, and altogether out of our control. Consider the difficulty of the very first step—of ascertaining what actually is the character of the individual, in each particular case that we examine. There is hardly any person living concerning some essential part of whose character there are not differences of opinion even among his intimate acquaintances; and a single action, or conduct continued only for a short time, goes a very little way toward ascertaining it. We can only make our observations in a rough way and en masse; not attempting to ascertain completely in any given instance, what character has been formed, and still less by what causes;” source