« AnteriorContinuar »
a venomous insect is too perfect to admit of the same interpretation.' Possibly death may be an evil which the Deity could not overcome or dispense with; and an envenomed wound may shorten the death-agony. Still, why was the sting not dipped in an anæsthetic? Why does the serpent not narcotise his victim ? Even if, as Livingstone asserts, it is soothing to be shaken in a lion's jaws, the case is exceptional. We still must ask why bodily pain, why mental pain, why everywhere so much suffering ? As Philo observes in connection with this subject, “If animals could be free from it an hour, they might enjoy a perpetual exemption from it; and it requires as particular a contrivance of their organs to produce that feeling as to endow them with sight, hearing, or any of the senses."
1 “The action of the sting affords telum imbelle (!) if a supply of poison, an example of the union of chymis- intense in quality, . .. had not been try and mechanism, such as, if it be furnished to it by the chemical elanot a proof of contrivance, nothing boration which was carried on in the is. First, as to the chymistry; how insect's body. And ... the poison highly concentrated must be the ... could not have attained its venom, which in so small a quantity effect or reached its enemy if ... can produce such powerful effects! it had not found there a machinery ... With respect to the mechanism, fitted to conduct it, &c., viz., an awl the sting is not a simple, but a com- to bore a hole, and a syringe to inpound instrument. . , . All this ma- ject the fluid.” – Paley's Natural chinery would have been useless Theology, chap. xix.
We may take leave of the old doubts, and address ourselves to the new. These may all be summed up under the one head-Darwinism. Under this aspect, Evolution has lately assumed cyclopean dimensions; first on account of the finishing-touch it has given to developmental cosmology ; secondly, by its explanation of the Origin of Species,—which, when applied to man, has a closer and more impressive interest.
The theory of Evolution is so familiar to all educated persons, and the works of its chief interpreters in this country- Darwin, Mr. Spencer, and Professor Huxleyare so intimately, or rather so widely known, that it would be impertinent to dwell as long upon this portion of our subject as upon others which you are less likely to have studied. Nevertheless, to omit all mention of it in a work professing to give an account of the creeds of the day, would, in spite of its familiarity, be absurd.
In my capacity as middle-man, I shall merely attempt a brief compendium of the doctrine; and since it is impossible to estimate its philosophical and scientific merit without some acquaintance with the ultimate laws of Nature upon which it is founded, we may begin with a hasty glance at the “First Principles ” of Mr. Spencer.
To the mind of Hume, these principles, as you have seen, were present in no very different form to that in which they are now set forth. As to Kant, there is hardly an important theory propounded by modern science with which he was not more or less conversant. This, however, in no wise detracts from the excellence of Mr.
Spencer's labours. In the application of the known laws of Nature to the system we are about to survey, Mr. Spencer is without a rival; and possibly on this account posterity may award him a representative place in the English philosophy of the present age.
Evolution is described by Mr. Spencer as “the transformation of the homogeneous into the heterogeneous.” It also implies a change from the indefinite to the definite. “As well as an advance from simplicity to complexity, there is an advance from confusion to order, from undetermined arrangement to determined arrangement.” 1
The three essential axioms of Evolution are the indestructibility of matter, the persistence of force, and the continuity of motion. As the proofs of the first two entail somewhat lengthy metaphysical considerations, they will be dealt with in the third Series of Letters. Of the continuity of motion, we are told that it “is not only inductively inferred, but that it is a necessity of thought, &c. To think of motion as either being created or annihilated—to think of nothing becoming something, or something becoming nothing—is to establish in consciousness a relation between two terms of which one is absent from consciousness, which is impossible.” 2
Given the factors of Evolution, under what conditions do they work, and what are their products? The first condition is mobility. “The constituents of an aggregate cannot be rearranged unless they are movable,” &c. But the mobility must be within limits, for “no considerable degree of evolution is exhibited where there is either great mobility of the parts or great immobility of them.”3 For example, "in liquids the cohesion of the units is so slight that there is no permanency in their relations of position to each other. Such rearrangement as any incident force generates is immediately destroyed again by the momentum of the constituents moved,” &c. Freedom of individual action is essential to social development;
1 Pirst Principles, p. 176. ? Page 248. 3 Page 339.
but the freedom of savage tribes, where there is “extremely little cohesion among the units," is as unfavourable to social heterogeneity as the restraining power of “accumulated traditions, laws, and usages, and long-fixed class arrangements” common to societies of the Oriental type.
Evolution is compelled to surmise some point of departure. It starts from nebulous matter-matter in a homogeneous state; and “the condition of homogeneity is a condition of unstable equilibrium.”1 This is evident, for the following simple reason: “Each unit of a homogeneous whole must be differently affected from any of the rest by the aggregate action of the rest upon it. The resultant force exercised by the aggregate on each unit, being in no two cases alike in both amount and direction, cannot produce like effects on the units. And the various positions of the parts in relation to any incident force preventing them from receiving it in uniform amounts and directions, a further difference in the effects wrought on them is inevitably produced.” 2
Even supposing uniform force to act upon a uniform mass, we still get redistribution or change both in the mass and in the force. In the mass, “ because the parts of the mass stand in different relations to the force.” In the force, because “ action and reaction, being equal and opposite, it follows that in differentiating the parts on which it falls in unlike ways, the incident force must itself be correspondingly differentiated.”
A further consequence is, that the effects produced are continually being multiplied, so that “each stage of evolution must initiate a higher stage.” Examples: “If the earth was formed by the concentration of diffused matter, it must at first have been incandescent, &c. The earth, falling in temperature, must contract, &c. As the cooling progresses and the envelope thickens, the ridges consequent on these contractions must become greater, rising 1 Page 358.
2 Page 386.
ultimately into hills and mountains, &c. As the earth's solid envelope thickened, the areas of elevation and depression became greater. In the place of islands more or less homogeneously scattered over an all-embracing sea, there must have gradually arisen heterogeneous arrangements of continents and ocean, such as we now know,"
“A like multiplication of effects must happen in the unfolding organism, &c. Doubtless, we are still in the dark respecting those mysterious properties which make the germ, when subject to fit influences, undergo the special changes beginning this series of transformation. All here contended for is, that, given a germ possessing these mysterious properties, the evolution of an organism from it depends, in part, on that multiplication of effects which we have seen to be a cause of evolution in general, &c." As instances of like germs evolving into unlike forms, according to circumstances, we have the larva of the working bee changed into that of the queen-bee by change of food at a certain period of its growth. “The ovum of the tape-worm getting into the intestines of one animal unfolds into the form of its parent; but if carried into other parts of the system, or into the intestine of some unlike animal, it becomes one of the sac-like creatures called by naturalists Cysticerci, or Conuri, or Echinoccoci, &c.”
The changes on the earth's surface consequent on upheavals and subsidences would not only produce changes of climate and temperature, but would entail complete changes in the flora and fauna of the altered regions. Changes in physical conditions would modify or destroy plants. Changes in physical conditions and in food would produce change of habits, and hence modification in animals. Redistribution due to geographical changes would engender variations by crossing. “The sensible or insensible alterations thus produced in each species would
1 Page 394 ff.