| PART I. |
| WHAT IS EVOLUTION? |
| CHAPTER I. |
| ITS SCOPE AND DEFINITION. |
| PAGE |
| A type of evolution—Development of an egg | 3 |
| Universality of evolution—Pervades all nature and concerns all departments of thought—One half of all science—Illustrated (1) by human body, (2) by solar system, (3) by society, (4) by earth, (5) by organic kingdom—The term evolution usually, but not rightly, confined to this last | 3 |
| Definition of evolution—I. Progressive change—Shown in the animal body, or the Ontogenic series—In the animal scale, or the Taxonomic series—In the geological, or Phylogenic series—The three series similar, though not identical | 8 |
| II. Change according to certain laws—Three laws of succession of organic forms | 11 |
| (a) Law of differentiation—Early forms are generalized; afterwards separated into specialized forms—Illustrated by fishes, by birds—Whole process of differentiation illustrated by growth and branching of a tree | 11 |
| (b) Law of progress of the whole—Mistake of confounding evolution with upward progress—How far true, and how far false—Illustrated by branching tree—Examples of this mistake in the popular mind—In the scientific mind | 13 |
| (c) Law of cyclical movement—Shown in geological history—Age of mollusks, fishes, reptiles, mammals, man—Illustrated again by a branching tree—Increasing complexity as well as height—Illustrated by diagram | 16 |
| The above three laws are laws of evolution—Differentiation—Shown in the development of an egg, the type of evolution | 19 |
| Progress of the whole—Not progress of all parts—Shown in the development of an egg | 22 |
| Cyclical movement—Less fundamental than other two—Shown in Ontogeny of body, of mind—Increasing complexity—Necessity of continued advance—Otherwise deterioration—All these laws shown in progress of society—-Differentiation shown—Progress of the whole but not of all parts shown—Cyclical movement shown—In social evolution, however, there is another element, viz., conscious voluntary progress—-This kind of evolution contrasted with the other | 22 |
| III. Change by means of resident forces—This is the point of dispute—Sense in which we use term resident forces—Does not touch question of origin of natural forces | 27 |
| The two views of the origin of organic forms briefly contrasted—As to whether natural or supernatural—As to variability, definite or indefinite—As to change from one species to another by transmutation or substitution—As to universality of law of continuity | 29 |
| CHAPTER II. |
| THE RELATION OF LOUIS AGASSIZ TO THE THEORY OF EVOLUTION. |
| General misunderstanding on this subject—Necessary to give sketch of history of the idea—Greeks, Lucretius, Swedenborg, and Kant—First scientific presentation by Lamarck—General character of Lamarck’s views—Failed, and rightly so—Next, Chambers’s “Vestiges of Creation”—Its general character—Failed, and rightly so—Some think this unfortunate—Why not so—An obstacle must be removed and a basis laid | 32 |
| The obstacle removed—Old views in regard to forces—Correlation of forces established—But vital force considered exception—Therefore living forms also supposed exception to mode of origin of other forms—Then vital forces also correlated—Therefore, a priori probable that living forms also correlated with other forms as to mode of origin—Thus obstacle removed | 35 |
| The basis laid—Agassiz laid inductive basis of evolution, although he refused to build—He established the laws of evolution and perfected the method of comparison—Importance of method discussed—The method of notation—The method of experiment—The difficulty of applying these to life phenomena—Method of comparison shown—(1) In Taxonomic series—(2) In Ontogenic series—(3) In Phylogenic series—Cuvier the great worker by comparison in the Taxonomic series—Agassiz in the Ontogenic and Phylogenic—Agassiz also established the three laws of evolution given in previous chapter—Thus he laid foundation—Why he did not build—Supposed identity of evolution and materialism—The obstacle being removed and the basis laid, when evolution again brought forward it was universally accepted, because the world was prepared—Place of Agassiz and Darwin compared—Formal science vs. physical science—Illustrated by relation of Kepler to Newton—Relation of Agassiz to time cosmos similar to that of Kepler to space cosmos—So Darwin to Newton—Some reflections on the above—Gravitation is the law of space cosmos—Evolution of time cosmos—Of the divine spheral music gravitation is the chordal harmony and evolution the melody | 37 |
| PART II. |
| EVIDENCES OF THE TRUTH OF EVOLUTION. |
| CHAPTER I. |
| | 232 |
| Law of cross-breeding—Effect of close breeding—Of crossing varieties to a limit—The law investigated—Reproduction in lowest organisms—Fission—Gemmation—Internal gemmation—Sex introduced—Effect of, is funding of differences in offspring and tendency to variation—Sexual and non-sexual reproduction compared—Separation of sex elements—Of sex-individuals—Introduction of sex-attraction—Funding of greater differences in offspring—Crossing of varieties—Diagram illustrating effect in vigor—Effect also in plasticity—Application of these principles—Necessity of sexual isolation to produce species—Origin of cross-sterility and thus of species by Dr. Romanes’s idea—Why artificial varieties are cross-fertile—Geographical species sometimes cross-fertile—Application of principles—Absence of intermediate links in natural species explained—Under what conditions such are found—Further explanation of this point—Illustrated by a growing tree | 236 |
| Objection answered—Intermediate links ought to be found fossil—Answer (1) Imperfection of record. (2) The term species indefinite. (3) Transitions between all other taxonomic groups abundant. (4) Between species, also, both living and fossil—Of fossil, Planorbis of Steinheim—Other examples—(5) Why transition-forms are rare—Answer—Changes in every department of nature are paroxysmal—Illustrated—So the steps of evolution paroxysmal—Critical periods in evolution—Causes of rapid advance—Apparent discontinuity between species—(1) changes paroxysmal—(2) Brooks’s idea—Male sex is the progressive element—Illustrated by society—Effect of prosperous times—Mrs. Treat’s experiments—Hard times produce excess of males, and therefore tend to diversity—Summary | 248 |
| Objection—Egyptian drawings and mummy plants, show no change—Answer (1) Time too short. (2) We are now in time of slow change. (3) All species don’t change, most become extinct. (4) Evolution is probably slower now than formerly—Reasons for so thinking—Organic evolution approaching completion—Other supposed objections | 265 |
| Origin of beauty—Explanation of, in higher animals—In flowering plants—But in many cases we can’t explain | 269 |
| Incipient organs—Difficulty of explaining—But these are not objections to the fact of evolution, but only to the sufficiency of the present theories of evolution. Therefore, all discussion concerns special theories. The fact of evolution is certain | 270 |
| PART III. |
| THE RELATION OF EVOLUTION TO RELIGIOUS THOUGHT. |
| CHAPTER I. |
| INTRODUCTORY. |
| Evolution if true affects every department of thought—What will be its effect on religious beliefs?—Objection that truth-seeker has nothing to do with effects—Answered | 275 |
| Relation of the true and the good | 277 |
| Relation of philosophy to life—The three necessary elements of a rational philosophy—Application to the case in hand—And the subject of Part III justified—Exaggerated fears—Different forms of the conflict of science and religion—(1) Heliocentric theory—First effect and final result—(2) Law of gravitation—Effect and result—(3) Antiquity of the earth and cosmos—Effect and result—(4) Antiquity of man—(5) Evolution | 277 |
| CHAPTER II. |
| THE RELATION OF EVOLUTION TO MATERIALISM. |
| Supposed identity—Tendency of the age—Evolution does not differ in this regard from other laws of Nature—Absurdity of identification illustrated in many ways—(1) Effect of discovery of process of making—(2) Effect of new form of old truth—(3) Manner in which vexed questions are settled and rational philosophy found—Illustrated—A true philosophy is a reconciliation of partial views—Three possible views of origin of individuals and of species; two one-sided and partial, and the third combining, reconciling, and therefore rational—The only bar to speedy reconciliation is dogmatism—Theological and scientific—The appropriate rebuke for each—Therefore evolution does not differ from other laws in regard to its relation to materialism—Nevertheless, great changes in our traditional beliefs impending—Main changes are notions concerning God, Nature, and man, in their relations to one another | 284 |
| CHAPTER III. |
| THE RELATION OF GOD TO NATURE. |
| The issue in regard to this relation stated—The growth of the issue described—The old view of direct relation—The effect of science and the resulting view—The compromise—Destroyed by evolution—The issue forced—The alternative view—Immanence of Deity—This view explained—Objection of idealism—Answered—It is not subjective idealism—Objection of pantheism—Answer deferred—Objection that the view is incompatible with practical life—Answered | 297 |
| CHAPTER IV. |
| THE RELATION OF MAN TO NATURE. |
| The two extreme views in this regard—They are views from different points, psychical and material—The latter very productive in modern times—But many fear the final effect—Reconciliation is possible—Scientific materialism has two branches—Physiological branch explained—Conclusion—Answer—Relation of psychic to brain changes is inscrutable—The mystery illustrated—Outside and inside view—Different from other phenomena in this regard |
