In the modern world, progress in the art and science of living has not kept pace with progress in the other arts and sciences. Man does not lead a better and a happier life than he used to do. There are many indications that human conduct is getting worse, and that men are more discontented, more miserable than they used to be. One means of moral progress would be to provide a sound and universally accepted code of ethics. The world would then have, at least, a moral standard by which human actions could be judged. It would go a long way toward forming a healthy public opinion on all moral questions. The Christian religion furnishes the highest moral standard ever manifested to the world. Unfortunately, there are two fundamentally different conceptions of Christian morality the Catholic and the Protestant conception. Perhaps if we put them side by side the truth will appear. This book begins: "Is man a moral or a merely physical agent? Are all man's thoughts, words, and actions determined by merely physical and necessary laws like those of electricity or steam? If man is a merely physical agent, then morality is only a department of physics, and, without doubt, it will be an important department of physics. It is important for us to know the laws which govern the action of gravitation, or of electricity, or of steam, but it is still more important for us to know the laws which govern the action of men. If man is nothing but matter and force, by patient study we shall be able to predict his every thought, word, and action with as much certainty as we can predict the action of a steam-engine or of a motor-car. Such knowledge would be invaluable for governments, employers, and parents. It would not be less valuable for the private citizen, the employed, and for children still under parental sway. "But is man a merely physical agent, a mere natural machine? Is man's action determined solely by the antecedents and conditions of action, so that if we knew them all we could predict infallibly what that action would be? Or is there something in man which clearly distinguishes his action from that of merely physical causes?"