"Change in our views seems to be the only permanent phenomenon, and in no science has the maxim: "Much arises which has already perished, and what is now honored is already declining," attained such extended verification as in the very science of medicine. Even so in this same science has been proven the truth of that other saying: "As long at man struggles he errs". To err in its struggles after the truth is, however, according to the resigned expression of Lessing, the portion of humanity, and absolute truth is of God alone."