"One should become so familiar with the structure as to have the feeling of being, in full vitality and sentiment, part of it and of all its elements. ...it is necessary to achieve a sincere Einfühlung [empathy] of the process of resistence... through the deformation that is always essentially united with the process of stressing. ...[T]he comprehension of a structure requires intuitive knowledge of the ethology of its resistance and of its constituent materials."