In _Mechanism in Thought and Morals_, we find a deal of psychology as well as science. "It is in the moral world," says Doctor Holmes, "that materialism has worked the strangest confusion. In various forms, under imposing names and aspects, it has thrust itself into the moral relations, until one hardly knows where to look for any first principles without upsetting everything in searching for them. "The moral universe includes nothing but the exercise of choice: all else is machinery. What we can help and what we cannot help are on two sides of a line which separates the sphere of human responsibility from that of the Being who has arranged and controls the order of things. "The question of the freedom of the will has been an open one, from the days of Milton's demons in conclave to the noteworthy essay of Mr. Hazard, our Rhode Island neighbor. It still hangs suspended between the seemingly exhaustive strongest motive argument and certain residual convictions. The sense that we are, to a limited extent, self-determining; the sense of effort in willing; the sense of responsibility in view of the future, and the verdict of conscience in review of the past,--all of these are open to the accusation of fallacy; but they all leave a certain undischarged balance in most minds. We can invoke the strong arm of the _Deus in machina_, as Mr. Hazard, and Kant and others, before him have done. Our will may be a primary initiating cause or force, as unexplainable, as unreducible, as indecomposable, as impossible if you choose, but as real to our belief as the _oeternitas a parte ante_. The divine foreknowledge is no more in the way of delegated choice than the divine omnipotence is in the way of delegated power. The Infinite can surely slip the cable of the finite if it choose so to do." With outspoken braveness Doctor Holmes rejects "the mechanical doctrine which makes me," he says, "the slave of outside influences, whether it work with the logic of Edwards, or the averages of Buckle; whether it come in the shape of the Greek's destiny, or the Mahometan's fatalism." But he claims, too, the right to eliminate all mechanical ideas which have crowded into the sphere of intelligent choice between right and wrong. "The pound of flesh," he declares, "I will grant to Nemesis; but in the name of human nature, not one drop of blood,--not one drop." And this leads us to speak of Doctor Holmes' religious views. He attended King's Chapel, and is classed among the most liberal-minded of the Unitarian creed. When chairman of the Boston Unitarian Festival, in 1877, he gave the following list of certain theological beliefs that he has always delighted to combat. "May I," he begins, "without committing any one but myself, enumerate a few of the stumbling blocks which still stand in the way of some who have many sympathies with what is called the liberal school of thinkers?