685 



SCIENTIFIC SIDE-LIGHTS 



Theories 



the profound and experienced thinker, re- 

 garding the " ultimate mechanical cause " 

 of all motion. HUMIJOLDT Cosmos, vol. iii, 

 int., p. 22. (H., 1897.) 



3388. THEORIES, CONFLICTING, 

 OF GEOLOGISTS How Alpine Valleys Were 

 Formed Fracture vs. Erosion. To the phys- 

 ical geologist the conformation of the Alps 

 and of mountain regions generally consti- 

 tutes one of the most interesting problems 

 of the present day. To account for this con- 

 formation, two hypotheses have been ad- 

 vanced, which may be respectively named 

 the hypot'iesis of fracture and tl hypothe- 

 sis of erosion. Those who adopt the former 

 maintain that the forces by which the Alps 

 were elevated produced fissures in the earth's 

 crust, and that the valleys of the Alps are 

 the tracks of these fissures. Those who hold 

 the latter hypothesis maintain that the val- 

 leys have been cut out by the action of ice 

 and water, the mountains themselves being 

 the residual forms of this grand sculpture. 

 To the erosive action here indicated must be 

 added that due to the atmosphere (the sev- 

 erance and detachment of rocks by rain 

 and frost), as affecting the forms of the 

 more exposed and elevated peaks. TYNDALL 

 Hours of Exercise in the Alps, ch. 20, p. 219. 

 (A., 1898.) 



3389. THEORIES FRAMED IN THE 

 IDEAL WORLD Their Verification in the 

 World of Fact The Final Test the Gift of 

 Prophecy (2 Pet. i, 19). Tho the region of 

 physical theory lies thus behind the world 

 of senses, the verifications of theory occur 

 in that world. Laying the theoretic concep- 

 tion at the root of matters, we determine by 

 deduction what are the phenomena which 

 must of necessity grow out of this root. 

 If the phenomena thus deduced agree with 

 those of the actual world, it is a presump- 

 tion in favor of the theory. If, as new 

 classes of phenomena arise, they also are 

 found to harmonize with theoretic deduc- 

 tion, the presumption becomes still stronger. 

 If, finally, the theory confers prophetic vi- 

 sion upon the investigator, enabling him to 

 predict the occurrence of phenomena which 

 have never yet been seen, and if those pre- 

 dictions be found on trial to be rigidly cor- 

 rect, the persuasion of the truth of the 

 theory becomes overpowering. TYNDALL 

 Lectures on Light, lect. 2, p. 47. (A., 1898.) 



3390. THEORIES OF CREATION 



False Alternatives of Spencer Creator Not 

 External, but Immanent. Spencer says: 

 " The verbally intelligent suppositions re- 

 specting the origin of the universe are three : 

 (1) It is self-existent; (2) it is self -cre- 

 ated ; ( 3 ) it is created by an external agen- 

 cy." On these it may be remarked that the 

 second is scarcely even " verbally intelli- 

 gent"; it seems to be a contradiction in 

 terms. The third admits of an important 

 modification, which was manifest to Spi- 

 noza, if not to Spencer namely, that the 



Creator may nay, must be not merely 

 " external," but within the universe as well. 

 If there is a God, he must be in the uni- 

 verse as a pervading power, and in every 

 part of it, and must not be shut out from 

 his own work. This mistaken conception of 

 God as building himself out of his own uni- 

 verse and acting on it by external force is 

 both irrational and unscientific, being, for 

 example, quite at variance with the analogy 

 of force and life. Rightly understood, there- 

 fore, Spencer's alternatives resolve them- 

 selves into two either the universe is self- 

 existent, or it is the work of a self-existent 

 Creator pervading all things with his power. 

 DAWSON Facts and Fancies in Modern 

 Science, lect. 1, p. 29. (A. B. P. S.) 



3391. THEORIES OF SLOW 

 GROWTH Undulatory Theory of Light- 

 Not in a moment are great theories elabo- 

 rated : the facts which demand them are first 

 called into prominence by observant minds; 

 then, to the period of observation succeeds 

 a period of pondering and of tentative ex- 

 planation. By such efforts the human mind 

 is gradually prepared for the final theoretic 

 illumination. The colors of thin plates, for 

 example, occupied tne attention of the cele- 

 brated Robert Boyle. In his " Experimental 

 History of Colors " he contends against the 

 schools which affirmed that color was " a 

 penetrative quality that reaches to the in- 

 nermost parts of the object," adducing op- 

 posing facts. [It was not till a century 

 later, however, that the undulatory theory 

 of light was finally established by Thomas 

 Young.] TYNDALL Lectures on Light, lect. 

 2, p. 8. (A., 1898.) 



3392. THEORIES OF THE HEAV- 

 ENS Pictures Made to Illustrate A True Map 

 of the Shies Preconceived Opinions Disre- 

 garded. It occurred to me very early in my 

 inquiry into the great problem, and before I 

 had fully investigated the long and noble 

 series of researches by which Sir W. Her- 

 schel had attempted to master it, that this 

 was a case where the mental vision must be 

 assisted by the bodily vision. It is singular 

 that hitherto, so far as I know (and I think 

 little that has been done on the subject has 

 escaped my reading), the idea of picturing 

 the results obtained by telescopic scrutiny 

 had been altogether overlooked. I do not 

 here refer to pictures illustrating theories 

 of the universe. Every student of astronomy 

 knows that Sir W. Herschel was careful to 

 give diagrams illustrating his successive 

 conceptions of the structure of the universe. 

 But such illustrations as these, tho neces- 

 sary and useful, cannot throw any light 

 on the structure of the universe, since they 

 illustrate theories already formed, not facts 

 on which theories are to be based. What 

 seemed to me most desirable was that charts 

 should be constructed on which the results 

 of telescopic observation should be carefully 

 mapped down without reference to any pre- 

 conceived opinions, and solely with the in- 



