Evolution: Its Nature, Its Evidence, and Its Relation to Religious Thought

CHAPTER I.. Its Scope and Definition.

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.

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._

EVIDENCES OF THE TRUTH OF EVOLUTION.

CHAPTER I.

GENERAL EVIDENCES OF EVOLUTION AS A UNIVERSAL LAW.

Evolution is continuity, causal relation, gradual becoming --Increasing acceptance of this idea--First accepted for inorganic forms, mountains, continents and seas, rocks and soils, earth as a whole, heavenly bodies--Therefore acknowledged for all inorganics--Influence of geology in bringing about this change--Organic forms: acknowledged for individuals, true for classes, orders, families, genera --Races and varieties also formed gradually--Artificial species formed gradually--Examples of gradual changes in wild species--Hyatt’s researches--Other examples--Summing up of general evidence--Sufficient ground for induction-- But evolution is not only inductively probable but certain, axiomatic--It is the law of causation applied to forms, and therefore a necessary truth 53

CHAPTER II.. Special Proofs of Evolution.

SPECIAL PROOFS OF EVOLUTION.

Introductory.

Special proofs necessary--Evolution, though certain, is not yet accepted by the popular mind--Different departments from which proofs are drawn 67

Origin of new organic forms; the old view briefly stated-- Necessary to give a brief statement of theories--Old view-- Permanency of specific types--Supernatural origin of species --Centers of creation--Explanation of facts of geographical distribution--Of geological distribution--Modification of extreme view--Variability, but within limits--Illustrated 68

The new view briefly stated--Indefinite variability of organic forms--Effect of environment on rigid forms--On plastic forms--Taxonomic groups represent degrees of kinship 72

Factors of evolution--(1) Physical environment--(2) Use and disuse of organs--(3) Natural selection--(4) Sexual selection--(5) Physiological selection--Its necessity shown --Its operation explained--Compared with natural selection --Cause of variation unknown--Explanation of this is the next great step in the theory of evolution 73

CHAPTER III.. The Grades of the Factors of Evolution and the Order of Their

THE GRADES OF THE FACTORS OF EVOLUTION AND THE ORDER OF THEIR APPEARANCE.

Factors of evolution restated; their grades and the order of their introduction shown--Lamarckian factors, first in order because they precede sexual reproduction--(1) Environment--(2) Use and disuse--With sexual reproduction selective factors introduced--(3) Natural selection--(4) Physiological selection--(5) Sexual selection--With man was introduced (6) the rational factor--In this process two striking stages--viz., the introduction of sex and the introduction of reason--Effect of each to hasten the steps of evolution--The last by far the greater change 81

Contrast between organic and human evolution--(1) The meaning of term fittest in each--(2) Destiny of the weak and helpless in each--(3) The nature of evolutionary transformation in each--(4) The law of strait and narrow way applied in each--(5) Human evolution is a different kind and on a higher plane 88

Application to some questions of the day.

I. Neo-Darwinists, their position explained--Reasons for dissenting--(a) Lamarckian factors preceded all others-- (b) Though now subordinate, they still underlie and condition all other factors--(c) Shown by comparison of phylogeny with ontogeny 92

II. Human progress not identical with organic evolution--Mistake of the materialists--But neither is it wholly different, as some suppose 96

III. Neo-Darwinism is fatal to hopes of human progress--Reason may use freely Lamarckian factors, but can not use natural selection in the same way as Nature does 97

CHAPTER IV.. Special Proofs From the General Laws of Animal Structure, or

SPECIAL PROOFS FROM THE GENERAL LAWS OF ANIMAL STRUCTURE, OR COMPARISON IN THE TAXONOMIC SERIES.

General Principles.

Analogy and homology--Defined and illustrated by examples-- Wings and limbs--Lungs, gradual formation of, traced in the Taxonomic series--Traced in the Ontogenic series--Examples of homology in plants: tuber, cactus-leaf, acacia-leaf-- Definitions repeated and further explained--Common origin is the only explanation of homology 99

Primary divisions of the animal kingdom--True ground of such divisions is ability to trace homology--We take examples only from vertebrata and articulata--Compare to styles of architecture--To machines--To branching stem 107

CHAPTER V.. Proofs From Homologies of the Vertebrate Skeleton.

PROOFS FROM HOMOLOGIES OF THE VERTEBRATE SKELETON.

Common general plan--In several respects--Strongly suggestive of common origin--Details of structure demonstrative of the same 111

Special homology of vertebrate limbs 113

Fore-limbs--Comparison of fore-limbs of mammals, birds, reptiles, and fishes, part for part--Gradual changes in collar-bone and coracoid--In position of elbow--In bones of forearm--In position of wrist--In the tread--The term manus--Number of toes--Modifications for flight in various animals--For swimming in whales and fishes 113

Hind-limbs--Comparison of hind-limbs of several mammals-- Position of knee--Of heel--Plantigrade and digitigrade --Degrees of the latter--Number of toes--General law in regard to number of similar parts--Order of toe-dropping in artiodactyles--In perissodactyles 121

Genesis of the horse--Changes in foot-structure--Same true of other parts of skeleton--Only natural explanation is derivation--Nature compared with man in mode of working-- Angels--Griffins--Centaurs--Muscular and nervous systems --Visceral organs 126

CHAPTER VI.. Homologies of the Articulate Skeleton.

HOMOLOGIES OF THE ARTICULATE SKELETON.

Illustrations from this type--Plan of structure entirely different--General plan of structure explained and modifications shown--Shrimp--Modification of segments and of appendages for various purposes: swimming, walking, eating, sense--Illustrated by other crustaceans--By myriapods-- By marine worms--Crabs--Embryonic development of crabs-- insects--Modification of segments and appendages--Mouth parts of insects 132

Illustration of the law of differentiation--Cells--Segments --Individuals--Homologies in other departments of animals, but these are less familiar--Between primary groups, homology untraceable in adult forms--But these also probably connected by common origin--Different views as to origin of vertebrates 144

CHAPTER VII.. Proofs From Embryology, or Comparison in the Ontogenic Series.

PROOFS FROM EMBRYOLOGY, OR COMPARISON IN THE ONTOGENIC SERIES.

Resemblance of the three series--Frog, in Ontogeny passes through main stages of Taxonomy and Phylogeny--Resemblance only general--Many steps dropped out in Ontogeny 148

(1) Ontogeny of tailless amphibians--The frog: fish stage, perennibranch stage, caducibranch stage, aneural stage--Same stages in Phylogeny 150

(2) Aortic arches--Those of lizard described--Origin from gill-arches of fish--Change from one to the other in Ontogeny of a frog--Same changes in Phylogeny of lizard--Embryonic condition of mammalian heart and vessels--Gradual change and final condition in birds--In mammals--Gradual decrease in number of aortic arches as we go up the vertebrate scale-- Cogency of the argument from aortic arches 151

Continue reading Evolution: Its Nature, Its Evidence, and Its Relation to Religious Thought free in the Wunder reader →