the companion of Peter many fine pathological, juridical, or political rules in his head, of which he can even be a thorough teacher, and yet can easily stumble in their application, either because he is lacking in natural power of judgment (though not in understanding), and to be sure understands the universal in abstracto but cannot distinguish whether a case in concreto belongs under it, or also because he has not received adequate training for this judgment through examples and actual business.