CHAPTER VII

MODERN MATHEMATICS

=701.= Surely this is the golden age of mathematics.

--PIERPONT, JAMES.

_History of Mathematics in the

Nineteenth Century; Congress of Arts and

Sciences (Boston and New York, 1905),

Vol. 1, p. 493._

=702.= The golden age of mathematics--that was not the age of Euclid,

it is ours. Ours is the age when no less than six international

congresses have been held in the course of nine years. It is in

our day that more than a dozen mathematical societies contain a

growing membership of more than two thousand men representing the

centers of scientific light throughout the great culture nations

of the world. It is in our time that over five hundred scientific

journals are each devoted in part, while more than two score

others are devoted exclusively, to the publication of mathematics.

It is in our time that the _Jahrbuch über die Fortschritte der

Mathematik_, though admitting only condensed abstracts with

titles, and not reporting on all the journals, has, nevertheless,

grown to nearly forty huge volumes in as many years. It is in our

time that as many as two thousand books and memoirs drop from the

mathematical press of the world in a single year, the estimated

number mounting up to fifty thousand in the last generation.

Finally, to adduce yet another evidence of a similar kind, it

requires not less than seven ponderous tomes of the forthcoming

_Encyclopaedie der Mathematischen Wissenschaften_ to contain, not

expositions, not demonstrations, but merely compact reports and

bibliographic notices sketching developments that have taken place

since the beginning of the nineteenth century.--KEYSER, C. J.

_Lectures on Science, Philosophy and Art

(New York, 1908), p. 8._

=703.= I have said that mathematics is the oldest of the sciences; a

glance at its more recent history will show that it has the energy

of perpetual youth. The output of contributions to the advance of the

science during the last century and more has been so enormous that it

is difficult to say whether pride in the greatness of achievement in

this subject, or despair at his inability to cope with the multiplicity

of its detailed developments, should be the dominant feeling of the

mathematician. Few people outside of the small circle of mathematical

specialists have any idea of the vast growth of mathematical

literature. The Royal Society Catalogue contains a list of nearly

thirty-nine thousand papers on subjects of Pure Mathematics alone,

which have appeared in seven hundred serials during the nineteenth

century. This represents only a portion of the total output, the very

large number of treatises, dissertations, and monographs published

during the century being omitted.--HOBSON, E. W.

_Presidential Address British

Association for the Advancement of

Science, Section A, (1910); Nature, Vol.

84, p. 285._

=704.= Mathematics is one of the oldest of the sciences; it is

also one of the most active, for its strength is the vigour of

perpetual youth.--FORSYTH, A. R.

_Presidential Address British

Association for the Advancement of

Science, Section A, (1897); Nature, Vol.

56, p. 378._

=705.= The nineteenth century which prides itself upon the

invention of steam and evolution, might have derived a more

legitimate title to fame from the discovery of pure mathematics.

--RUSSELL, BERTRAND.

_International Monthly, Vol. 4 (1901),

p. 83._

=706.= One of the chiefest triumphs of modern mathematics

consists in having discovered what mathematics really is.

--RUSSELL, BERTRAND.

_International Monthly, Vol. 4 (1901),

p. 84._

=707.= Modern mathematics, that most astounding of intellectual

creations, has projected the mind’s eye through infinite time and

the mind’s hand into boundless space.--BUTLER, N. M.

_The Meaning of Education and other

Essays and Addresses (New York, 1905),

p. 44._

=708.= The extraordinary development of mathematics in the last

century is quite unparalleled in the long history of this most

ancient of sciences. Not only have those branches of mathematics

which were taken over from the eighteenth century steadily grown,

but entirely new ones have sprung up in almost bewildering

profusion, and many of them have promptly assumed proportions of

vast extent.--PIERPONT, J.

_The History of Mathematics in the

Nineteenth Century; Congress of Arts and

Sciences (Boston and New York, 1905),

Vol. 1, p. 474._

=709.= The Modern Theory of Functions--that stateliest of all the

pure creations of the human intellect.--KEYSER, C. J.

_Lectures on Science, Philosophy and Art

(New York, 1908), p. 16._

=710.= If a mathematician of the past, an Archimedes or even a

Descartes, could view the field of geometry in its present

condition, the first feature to impress him would be its lack of

concreteness. There are whole classes of geometric theories which

proceed not only without models and diagrams, but without the

slightest (apparent) use of spatial intuition. In the main

this is due, to the power of the analytic instruments of

investigations as compared with the purely geometric.

--KASNER, EDWARD.

_The Present Problems in Geometry;

Bulletin American Mathematical Society,

1905, p. 285._

=711.= In Euclid each proposition stands by itself; its

connection with others is never indicated; the leading ideas

contained in its proof are not stated; general principles do not

exist. In modern methods, on the other hand, the greatest

importance is attached to the leading thoughts which pervade the

whole; and general principles, which bring whole groups of

theorems under one aspect, are given rather than separate

propositions. The whole tendency is toward generalization. A

straight line is considered as given in its entirety, extending

both ways to infinity, while Euclid is very careful never to

admit anything but finite quantities. The treatment of the

infinite is in fact another fundamental difference between the

two methods. Euclid avoids it, in modern mathematics it is

systematically introduced, for only thus is generality obtained.

--CAYLEY, ARTHUR.

_Encyclopedia Britannica (9th edition),

Article “Geometry.”_

=712.= This is one of the greatest advantages of modern geometry

over the ancient, to be able, through the consideration of

positive and negative quantities, to include in a single

enunciation the several cases which the same theorem may present

by a change in the relative position of the different parts of a

figure. Thus in our day the nine principal problems and the

numerous particular cases, which form the object of eighty-three

theorems in the two books _De sectione determinata_ of Appolonius

constitute only one problem which is resolved by a single

equation.--CHASLES, M.

_Histoire de la Géométrie, chap. 1,

sect. 35._

=713.= Euclid always contemplates a straight line as drawn

between two definite points, and is very careful to mention when

it is to be produced beyond this segment. He never thinks of the

line as an entity given once for all as a whole. This careful

definition and limitation, so as to exclude an infinity not

immediately apparent to the senses, was very characteristic of

the Greeks in all their many activities. It is enshrined in the

difference between Greek architecture and Gothic architecture,

and between Greek religion and modern religion. The spire of a

Gothic cathedral and the importance of the unbounded straight

line in modern Geometry are both emblematic of the transformation

of the modern world.--WHITEHEAD, A. N.

_Introduction to Mathematics (New York,

1911), p. 119._

=714.= The geometrical problems and theorems of the Greeks always

refer to definite, oftentimes to rather complicated figures. Now

frequently the points and lines of such a figure may assume very

many different relative positions; each of these possible cases

is then considered separately. On the contrary, present day

mathematicians generate their figures one from another, and are

accustomed to consider them subject to variation; in this manner

they unite the various cases and combine them as much as possible

by employing negative and imaginary magnitudes. For example, the

problems which Appolonius treats in his two books _De sectione

rationis_, are solved today by means of a single, universally

applicable construction; Apollonius, on the contrary, separates

it into more than eighty different cases varying only in

position. Thus, as Hermann Hankel has fittingly remarked, the

ancient geometry sacrifices to a seeming simplicity the true

simplicity which consists in the unity of principles; it attained

a trivial sensual presentability at the cost of the recognition

of the relations of geometric forms in all their changes and in

all the variations of their sensually presentable positions.

--REYE, THEODORE.

_Die synthetische Geometrie im Altertum

und in der Neuzeit; Jahresbericht der

Deutschen Mathematiker Vereinigung, Bd.

2, pp. 346-347._

=715.= It is known that the mathematics prescribed for the high

school [Gymnasien] is essentially Euclidean, while it is modern

mathematics, the theory of functions and the infinitesimal

calculus, which has secured for us an insight into the mechanism

and laws of nature. Euclidean mathematics is indeed, a prerequisite

for the theory of functions, but just as one, though he has

learned the inflections of Latin nouns and verbs, will not thereby

be enabled to read a Latin author much less to appreciate the

beauties of a Horace, so Euclidean mathematics, that is the

mathematics of the high school, is unable to unlock nature and

her laws. Euclidean mathematics assumes the completeness and

invariability of mathematical forms; these forms it describes with

appropriate accuracy and enumerates their inherent and related

properties with perfect clearness, order, and completeness, that

is, Euclidean mathematics operates on forms after the manner that

anatomy operates on the dead body and its members.

On the other hand, the mathematics of variable

magnitudes--function theory or analysis--considers mathematical

forms in their genesis. By writing the equation of the parabola,

we express its law of generation, the law according to which the

variable point moves. The path, produced before the eyes of the

student by a point moving in accordance to this law, is the

parabola.

If, then, Euclidean mathematics treats space and number forms

after the manner in which anatomy treats the dead body, modern

mathematics deals, as it were, with the living body, with growing

and changing forms, and thus furnishes an insight, not only into

nature as she is and appears, but also into nature as she

generates and creates,--reveals her transition steps and in so

doing creates a mind for and understanding of the laws of

becoming. Thus modern mathematics bears the same relation to

Euclidean mathematics that physiology or biology ... bears to

anatomy. But it is exactly in this respect that our view of

nature is so far above that of the ancients; that we no longer

look on nature as a quiescent complete whole, which compels

admiration by its sublimity and wealth of forms, but that we

conceive of her as a vigorous growing organism, unfolding

according to definite, as delicate as far-reaching, laws; that we

are able to lay hold of the permanent amidst the transitory, of

law amidst fleeting phenomena, and to be able to give these their

simplest and truest expression through the mathematical formulas.

--DILLMANN, E.

_Die Mathematik die Fackelträgerin einer

neuen Zeit (Stuttgart, 1889), p. 37._

=716.= The Excellence of _Modern Geometry_ is in nothing more

evident, than in those full and adequate Solutions it gives to

Problems; representing all possible Cases in one view, and in one

general Theorem many times comprehending whole Sciences; which

deduced at length into Propositions, and demonstrated after the

manner of the _Ancients_, might well become the subjects of large

Treatises: For whatsoever Theorem solves the most complicated

Problem of the kind, does with a due Reduction reach all the

subordinate Cases.--HALLEY, E.

_An Instance of the Excellence of Modern

Algebra, etc.; Philosophical

Transactions, 1694, p. 960._

=717.= One of the most conspicuous and distinctive features of

mathematical thought in the nineteenth century is its critical

spirit. Beginning with the calculus, it soon permeates all analysis,

and toward the close of the century it overhauls and recasts the

foundations of geometry and aspires to further conquests in

mechanics and in the immense domains of mathematical physics....

A searching examination of the foundations of arithmetic and the

calculus has brought to light the insufficiency of much of the

reasoning formerly considered as conclusive.--PIERPONT, J.

_History of Mathematics in the

Nineteenth Century; Congress of Arts and

Sciences (Boston and New York, 1905),

Vol. 1, p. 482._

=718.= If we compare a mathematical problem with an immense rock,

whose interior we wish to penetrate, then the work of the Greek

mathematicians appears to us like that of a robust stonecutter,

who, with indefatigable perseverance, attempts to demolish the

rock gradually from the outside by means of hammer and chisel;

but the modern mathematician resembles an expert miner, who first

constructs a few passages through the rock and then explodes it

with a single blast, bringing to light its inner treasures.

--HANKEL, HERMANN.

_Die Entwickelung der Mathematik in den

letzten Jahrhunderten (Tübingen, 1884),

p. 9._

=719.= All the modern higher mathematics is based on a calculus

of operations, on laws of thought. All mathematics, from the

first, was so in reality; but the evolvers of the modern higher

calculus have known that it is so. Therefore elementary teachers

who, at the present day, persist in thinking about algebra and

arithmetic as dealing with laws of number, and about geometry as

dealing with laws of surface and solid content, are doing the

best that in them lies to put their pupils on the wrong track for

reaching in the future any true understanding of the higher

algebras. Algebras deal not with laws of number, but with such

laws of the human thinking machinery as have been discovered in

the course of investigations on numbers. Plane geometry deals

with such laws of thought as were discovered by men intent on

finding out how to measure surface; and solid geometry with such

additional laws of thought as were discovered when men began to

extend geometry into three dimensions.--BOOLE M. E.

_Logic of Arithmetic (Oxford, 1903),

Preface, pp. 18-19._

=720.= It is not only a decided preference for synthesis and a

complete denial of general methods which characterizes the

ancient mathematics as against our newer science [modern

mathematics]: besides this external formal difference there is

another real, more deeply seated, contrast, which arises from the

different attitudes which the two assumed relative to the use of

the concept of _variability_. For while the ancients, on account

of considerations which had been transmitted to them from the

philosophic school of the Eleatics, never employed the concept of

motion, the spatial expression for variability, in their rigorous

system, and made incidental use of it only in the treatment of

phonoromically generated curves, modern geometry dates from the

instant that Descartes left the purely algebraic treatment of

equations and proceeded to investigate the variations which an

algebraic expression undergoes when one of its variables assumes

a continuous succession of values.--HANKEL, HERMANN.

_Untersuchungen über die unendlich oft

oszillierenden und unstetigen

Functionen; Ostwald’s Klassiker der

exacten Wissenschaften, No. 153, pp.

44-45._

=721.= Without doubt one of the most characteristic features of

mathematics in the last century is the systematic and universal

use of the complex variable. Most of its great theories received

invaluable aid from it, and many owe their very existence to it.

--PIERPONT, J.

_History of Mathematics in the

Nineteenth Century; Congress of Arts and

Sciences (Boston and New York, 1905),

Vol. 1, p. 474._

=722.= The notion, which is really the fundamental one (and I

cannot too strongly emphasise the assertion), underlying and

pervading the whole of modern analysis and geometry, is that of

imaginary magnitude in analysis and of imaginary space in

geometry.--CAYLEY, ARTHUR.

_Presidential Address; Collected Works,

Vol. 11, p. 434._

=723.= The solution of the difficulties which formerly surrounded

the mathematical infinite is probably the greatest achievement of

which our age has to boast.--RUSSELL, BERTRAND.

_The Study of Mathematics; Philosophical

Essays (London, 1910), p. 77._

=724.= Induction and analogy are the special characteristics of

modern mathematics, in which theorems have given place to

theories and no truth is regarded otherwise than as a link in an

infinite chain. “_Omne exit in infinitum_” is their favorite

motto and accepted axiom.--SYLVESTER, J. J.

_A Plea for the Mathematician; Nature,

Vol. 1, p. 261._

=725.= The conception of correspondence plays a great part in

modern mathematics. It is the fundamental notion in the science

of order as distinguished from the science of magnitude. If the

older mathematics were mostly dominated by the needs of

mensuration, modern mathematics are dominated by the conception

of order and arrangement. It may be that this tendency of thought

or direction of reasoning goes hand in hand with the modern

discovery in physics, that the changes in nature depend not only

or not so much on the quantity of mass and energy as on their

distribution or arrangement.--MERZ, J. T.

_History of European Thought in the

Nineteenth Century (Edinburgh and

London, 1903), p. 736._

=726.= Now this establishment of correspondence between two

aggregates and investigation of the propositions that are carried

over by the correspondence may be called the central idea of

modern mathematics.--CLIFFORD, W. K.

_Philosophy of the Pure Sciences;

Lectures and Essays (London, 1901), Vol.

1, p. 402._

=727.= In our century the conceptions substitution and

substitution group, transformation and transformation group,

operation and operation group, invariant, differential invariant

and differential parameter, appear more and more clearly as the

most important conceptions of mathematics.--LIE, SOPHUS.

_Leipziger Berichte, No. 47 (1895), p.

261._

=728.= Generality of points of view and of methods, precision and

elegance in presentation, have become, since Lagrange, the common

property of all who would lay claim to the rank of scientific

mathematicians. And, even if this generality leads at times to

abstruseness at the expense of intuition and applicability, so

that general theorems are formulated which fail to apply to

a single special case, if furthermore precision at times

degenerates into a studied brevity which makes it more difficult

to read an article than it was to write it; if, finally, elegance

of form has well-nigh become in our day the criterion of the

worth or worthlessness of a proposition,--yet are these

conditions of the highest importance to a wholesome development,

in that they keep the scientific material within the limits which

are necessary both intrinsically and extrinsically if mathematics

is not to spend itself in trivialities or smother in profusion.

--HANKEL, HERMANN.

_Die Entwickelung der Mathematik in den

letzten Jahrhunderten (Tübingen, 1884),

pp. 14-15._

=729.= The development of abstract methods during the past few

years has given mathematics a new and vital principle which

furnishes the most powerful instrument for exhibiting the

essential unity of all its branches.--YOUNG, J. W.

_Fundamental Concepts of Algebra and

Geometry (New York, 1911), p. 225._

=730.= Everybody praises the incomparable power of the

mathematical method, but so is everybody aware of its

incomparable unpopularity.--ROSANES, J.

_Jahresbericht der Deutschen

Mathematiker Vereinigung, Bd. 13, p.

17._

=731.= Indeed the modern developments of mathematics constitute

not only one of the most impressive, but one of the most

characteristic, phenomena of our age. It is a phenomenon,

however, of which the boasted intelligence of a “universalized”

daily press seems strangely unaware; and there is no other great

human interest, whether of science or of art, regarding which the

mind of the educated public is permitted to hold so many

fallacious opinions and inferior estimates.--KEYSER, C. J.

_Lectures on Science, Philosophy and

Arts (New York, 1908), p. 8._

=732.= It may be asserted without exaggeration that the domain of

mathematical knowledge is the only one of which our otherwise

omniscient journalism has not yet possessed itself.

--PRINGSHEIM, ALFRED.

_Ueber Wert und angeblichen Unwert der

Mathematik; Jahresbericht der Deutschen

Mathematiker Vereinigung, (1904) p.

357._

=733.= [The] inaccessibility of special fields of mathematics,

except by the regular way of logically antecedent acquirements,

renders the study discouraging or hateful to weak or indolent

minds.--LEFEVRE, ARTHUR.

_Number and its Algebra (Boston, 1903),

sect. 223._

=734.= The majority of mathematical truths now possessed by us

presuppose the intellectual toil of many centuries. A mathematician,

therefore, who wishes today to acquire a thorough understanding of

modern research in this department, must think over again in

quickened tempo the mathematical labors of several centuries. This

constant dependence of new truths on old ones stamps mathematics

as a science of uncommon exclusiveness and renders it generally

impossible to lay open to uninitiated readers a speedy path to the

apprehension of the higher mathematical truths. For this reason,

too, the theories and results of mathematics are rarely adapted

for popular presentation.... This same inaccessibility of

mathematics, although it secures for it a lofty and aristocratic

place among the sciences, also renders it odious to those who have

never learned it, and who dread the great labor involved in

acquiring an understanding of the questions of modern mathematics.

Neither in the languages nor in the natural sciences are the

investigations and results so closely interdependent as to make it

impossible to acquaint the uninitiated student with single

branches or with particular results of these sciences, without

causing him to go through a long course of preliminary study.

--SCHUBERT, H.

_Mathematical Essays and Recreations

(Chicago, 1898), p. 32._

=735.= Such is the character of mathematics in its profounder

depths and in its higher and remoter zones that it is well nigh

impossible to convey to one who has not devoted years to its

exploration a just impression of the scope and magnitude of the

existing body of the science. An imagination formed by other

disciplines and accustomed to the interests of another field may

scarcely receive suddenly an apocalyptic vision of that infinite

interior world. But how amazing and how edifying were such a

revelation, if it only could be made.--KEYSER, C. J.

_Lectures on Science, Philosophy and Art

(New York, 1908), p. 6._

=736.= It is not so long since, during one of the meetings of the

Association, one of the leading English newspapers briefly

described a sitting of this Section in the words, “Saturday

morning was devoted to pure mathematics, and so there was nothing

of any general interest:” still, such toleration is better than

undisguised and ill-informed hostility.--FORSYTH, A. R.

_Report of the 67th meeting of the

British Association for the Advancement

of Science._

=737.= The science [of mathematics] has grown to such vast

proportion that probably no living mathematician can claim to

have achieved its mastery as a whole.--WHITEHEAD, A. N.

_An Introduction to Mathematics (New

York, 1911), p. 252._

=738.= There is perhaps no science of which the development has

been carried so far, which requires greater concentration and

will power, and which by the abstract height of the qualities

required tends more to separate one from daily life.

_Provisional Report of the American

Subcommittee of the International

Commission on the Teaching of

Mathematics; Bulletin American Society

(1910), p. 97._

=739.= Angling may be said to be so like the mathematics, that it

can never be fully learnt.--WALTON, ISAAC.

_The Complete Angler, Preface._

=740.= The flights of the imagination which occur to the pure

mathematician are in general so much better described in his

formulæ than in words, that it is not remarkable to find the

subject treated by outsiders as something essentially cold and

uninteresting--... the only successful attempt to invest

mathematical reasoning with a halo of glory--that made in this

section by Prof. Sylvester--is known to a comparative few, ....

--TAIT, P. G.

_Presidential Address British

Association for the Advancement of

Science (1871); Nature Vol. 4, p. 271._

Memorabilia Mathematica; or, the Philomath's Quotation-Book · 第 6 / 17 章