Most men, who have a special pursuit, find the necessity for recreation of some kind. Some take it in one way, and some in another. It has been my habit through life to seek occasional relief from the monotony of professional vocations in intellectual pursuits of another character. Having this habit—which I have found by experience has no tendency to lessen one's capacity for the duties of a profession, or one's relish of its occupations—I some years ago took up the study of the modern doctrine of animal evolution. Until after the death of the late Mr. Charles Darwin, I had not given a very close attention to this subject. The honors paid to his memory, and due to his indefatigable research and extensive knowledge, led me to examine his "Descent of Man" and his "Origin of Species," both of which I studied with care, and I trust with candor. I was next induced to examine the writings of Mr. Herbert Spencer on the subject of evolution, with which I had also been previously unacquainted except in a general way. I was a good deal surprised at the extent of Mr. Spencer's reputation as a thinker, and by the currency which his peculiar philosophy has had in this country, where it has led, among the young and inexperienced, as well as among older persons, to very incorrect habits of reasoning on subjects of the highest importance. The result of my studies of these writers is the present book. I have written it because I have seen, or believe that I have seen, where the conflict arises between some of the deductions of modern science and the principles which ought to regulate not only religious belief, but belief in anything that is not open to the direct observation of our senses. But I trust that I shall not be understood as having written for the purpose of specially defending the foundations of religious belief. This is no official duty of mine. How theologians manage, or ought to manage, the argument which is to convince men of the existence and methods of God, it is not for me to say. But a careful examination of the new philosophy has convinced me that those who are the special teachers of religious truth have need of great caution in the admissions or concessions which they make, when they undertake to reconcile some of the conclusions of modern scientists with belief in a Creator. I do not here speak of the Biblical account of the creation, but I speak of that belief in a Creator which is to be deduced from the phenomena of nature. While there are naturalists, scientists, and philosophers at the present day, whose speculations do not exclude the idea of a Supreme Being, there are others whose theories are entirely inconsistent with a belief in a personal God, the Creator and Governor of the universe. Moreover, although there are great differences in this respect between the different persons who accept evolution in some form, the whole doctrine of the development of distinct species out of other species makes demands upon our credulity which are irreconcilable with the principles of belief by which we regulate, or ought to regulate, our acceptance of any new matter of belief. The principles of belief which we apply in the ordinary affairs of life are those which should be applied to scientific or philosophical theories; and inasmuch as the judicial method of reasoning upon facts is at once the most satisfactory and the most in accordance with common sense, I have here undertaken to apply it to the evidence which is supposed to establish the hypothesis of animal evolution, in contrast with the hypothesis of special creations.

I am no ecclesiastic. I advance no arguments in favor of one or another interpretation of the Scriptures about which there is controversy among Christians. While I firmly believe that God exists, and that he has made a revelation to mankind, whereby he has given us direct assurance of immortality, I do not know that this belief disqualifies me from judging, upon proper principles of evidence, of the soundness of a theory which denies that he specially created either the body or the mind of man. How far the hypothesis of evolution, by destroying our belief that God specially created us, tends to negative any purpose for which we can suppose him to have made to us a revelation of our immortality, it is for the theologian to consider. For myself, I am not conscious that in examining the theory of evolution I have been influenced by my belief in what is called revealed religion. I have, at all events, studiously excluded from the argument all that has been inculcated by the Hebrew or the Christian records as authorized or inspired teachings, and have treated the Mosaic account of the creation like any other hypothesis of the origin of man and the other animals. The result of my study of the hypothesis of evolution is, that it is an ingenious but delusive mode of accounting for the existence of either the body or the mind of man; and that it employs a kind of reasoning which no person of sound judgment would apply to anything that might affect his welfare, his happiness, his estate, or his conduct in the practical affairs of life.

He who would truly know what the doctrine of evolution is, and to what it leads, must literally begin at the beginning. He must free his mind from the cant of agnosticism and from the cant of belief. He must refuse to accept dogmas on the authority of any one, be they the dogmas of the scientist, or of the theologian. He must learn that his mental nature is placed under certain laws, as surely as his corporeal structure; and he must cheerfully obey the necessities which compel him to accept some conclusions and to reject others. Keeping his reasoning powers in a well-balanced condition, he must prove all things, holding fast to that which is in conformity with sound deduction, and to that alone. But all persons may not be able to afford the time to pursue truth in this way, or may not have the facilities for the requisite research. It seemed to me, therefore, that an effort to do for them what they can not do for themselves would be acceptable to a great many people.

It may be objected that the imaginary philosopher whom I have introduced in some of my chapters under the name of Sophereus, or the searcher after wisdom, debating the doctrines of evolution with a supposed disciple of that school, whom I have named Kosmicos, is an impossible person. It may perhaps be said that the conception of a man absolutely free from all dogmatic religious teaching, from all bias to any kind of belief, and yet having as much knowledge of various systems of belief as I have imputed to this imaginary person, would in modern society be the conception of an unattainable character. My answer to this criticism would be that I felt myself at liberty to imagine any kind of character that would suit my purpose. How successfully I have carried out the idea of a man in mature life entirely free from all preconceived opinions, and forming his beliefs upon principles of pure reason, it is for my readers to judge. With regard to the other interlocutor in the dialogues, I hope it is not necessary for me to say that I do not impute all of his opinions or arguments to the professors of the evolution school, or to any section of it. He is a representative of the effects of some of their teachings, but not an individual portrait. But as, for the purposes of the antagonism, it was expedient to put into the mouth of this person whatever can be said in favor of the hypothesis of evolution, it became necessary to make him represent the dogmatic side of the theory; and thus to make the collision and contrast between the minds of the two debaters as strong as I could. Controversial discussion in the form of debate has been used from the time of Plato. While I have adopted a method, I have not presumed to imitate its great exemplars. But for the value of that method I shall presently cite weighty testimony. It was a relief to me to resort to it after having pursued the subject in the more usual form of discussion; and indeed it forced itself upon me as a kind of necessity, because it seemed the fairest way of presenting what could be said on both sides of the question. I hope it may have the good fortune to keep alive the interest of the reader, after he has perused the previous chapters.

One disadvantage of all positive writing or discourse is that there is no one to confute, to contradict, or to maintain the negative. At the bar, and in some public assemblies, there is an antagonist; and truth is elicited by the collision. But in didactic writing, especially on a philosophical topic, it is best to introduce an antagonist, and to make him speak in his own person. Two of the best thinkers of our time have forcibly stated the advantage—the necessity, in short—of personal debate. Mr. John Stuart Mill, in his essay on Liberty, observes that—

"The loss of so important an aid to the intelligent and living apprehension of a truth as is afforded by the necessity of explaining it to or defending it against opponents, though not sufficient to outweigh, is no trifling drawback from the benefits of its universal recognition. Where this advantage can not be had, I confess I should like to see the teachers of mankind endeavoring to provide a substitute for it; some contrivance for making the difficulties of the question as present to the learner's consciousness as if they were pressed upon him by a dissentient champion eager for his conversion.

"But instead of seeking contrivances for this purpose, they have lost those they formerly had. The Socratic dialectics, so magnificently exemplified in the dialogues of Plato, were a contrivance of this description. They were essentially a discussion of the great questions of life and philosophy, directed with consummate skill to the purpose of convincing any one, who had merely adopted the commonplaces of received opinion, that he did not understand the subject—that he as yet attached no definite meaning to the doctrines he professed, in order that, becoming aware of his ignorance, he might be put in the way to attain a stable belief, resting on a clear apprehension both of the meaning of doctrines and of their evidence. The school disputations of the middle ages had a similar object. They were intended to make sure that the pupil understood his own opinion, and (by necessary correlation) the opinion opposed to it, and could enforce the grounds of one and confute those of the other. The last-mentioned contests had, indeed, the incurable defect that the premises appealed to were taken from authority, not from reason; and as a discipline to the mind they were in every respect inferior to the powerful dialectics which formed the intellects of the 'Socratici viri.' But the modern mind owes far more to both than it is generally willing to admit; and the present modes of instruction contain nothing which in the smallest degree supplies the place either of the one or of the other.... It is the fashion of the present time to disparage negative logic—that which points out weakness in theory or errors in practice, without establishing positive truths. Such negative criticism would indeed be poor enough as an ultimate result, but as a means to attaining any positive knowledge or conviction worthy the name, it can not be valued too highly; and until people are again systematically trained to it there will be few great thinkers, and a low general average of intellect in any but the mathematical and physical departments of speculation. On any other subject no one's opinions deserve the name of knowledge, except so far as he has either had forced upon him by others, or gone through of himself, the same mental process which would have been required of him in carrying on an active controversy with opponents."

Mr. Grote, in his admirable work on "Plato and the other Companions of Socrates," has the following passage:

"Plato is usually extolled by his admirers as the champion of the Absolute—of unchangeable forms, immutable truth, objective necessity, cogent and binding on every one. He is praised for having refuted Protagoras, who can find no standard beyond the individual recognition and belief of his own mind or that of some one else. There is no doubt that Plato often talks in that strain, but the method followed in his dialogues, and the general principles of methods which he lays down here as well as elsewhere, point to a directly opposite conclusion. Of this the Phædrus is a signal instance. Instead of the extreme of generality, it proclaims the extreme of speciality. The objection which the Socrates of the Phædrus advances against the didactic efficacy of written discourse is founded on the fact that it is the same to all readers—that it takes no cognizance of the differences of individual minds nor of the same mind at different times. Socrates claims for dialectic debate the valuable privilege that it is constant action and reaction between two individual minds—an appeal by the inherent force and actual condition of each to the like elements in the other—an ever-shifting presentation of the same topics, accommodated to the measure of intelligence and cast of emotion in the talkers and at the moment. The individuality of each mind—both questioner and respondent—is here kept in view as the governing condition of the process. No two minds can be approached by the same road or by the same interrogation. The questioner can not advance a step except by the admission of the respondent. Every respondent is the measure to himself. He answers suitably to his own belief; he defends by his own suggestions; he yields to the pressure of contradiction and inconsistency when he feels them, and not before. Each dialogist is (to use the Protagorean phrase) the measure to himself of truth and falsehood, according as he himself believes it. Assent or dissent, whichever it may be, springs only from the free working of the individual mind in its actual condition then and there. It is to the individual mind alone that appeal is made, and this is what Protagoras asks for.