CHAPTER V

THE TEACHING OF MATHEMATICS

=501.= In mathematics two ends are constantly kept in view:

First, stimulation of the inventive faculty, exercise of

judgment, development of logical reasoning, and the habit of

concise statement; second, the association of the branches of

pure mathematics with each other and with applied science, that

the pupil may see clearly the true relations of principles and

things.

_International Commission on the

Teaching of Mathematics, American

Report; U. S. Bureau of Education,

Bulletin 1912, No. 4, p. 7._

=502.= The ends to be attained [in the teaching of mathematics in

the secondary schools] are the knowledge of a body of geometrical

truths, the power to draw correct inferences from given premises,

the power to use algebraic processes as a means of finding

results in practical problems, and the awakening of interest in

the science of mathematics.

_International Commission on the

Teaching of Mathematics, American

Report; U. S. Bureau of Education,

Bulletin 1912, No. 4, p. 7._

=503.= General preparatory instruction must continue to be the

aim in the instruction at the higher institutions of learning.

Exclusive selection and treatment of subject matter with

reference to specific avocations is disadvantageous.

_Resolution adopted by the German

Association for the Advancement of

Scientific and Mathematical Instruction;

Jahresbericht der Deutschen Mathematiker

Vereinigung (1896), p. 41._

=504.= In the secondary schools mathematics should be a part of

general culture and not contributory to technical training of any

kind; it should cultivate space intuition, logical thinking,

the power to rephrase in clear language thoughts recognized as

correct, and ethical and esthetic effects; so treated, mathematics

is a quite indispensable factor of general education in so far as

the latter shows its traces in the comprehension of the development

of civilization and the ability to participate in the further tasks

of civilization.

_Unterrichtsblätter für Mathematik und

Naturwissenschaft (1904), p. 128._

=505.= Indeed, the aim of teaching [mathematics] should be rather

to strengthen his [the pupil’s] faculties, and to supply a method

of reasoning applicable to other subjects, than to furnish him

with an instrument for solving practical problems.--MAGNUS, PHILIP.

_Perry’s Teaching of Mathematics

(London, 1902), p. 84._

=506.= The participation in the _general development of the

mental powers_ without special reference to his future vocation

must be recognized as the essential aim of mathematical

instruction.--REIDT, F.

_Anleitung zum Mathematischen Unterricht

an höheren Schulen (Berlin, 1906), p.

12._

=507.= I am of the decided opinion, that mathematical instruction

must have for its first aim a deep penetration and complete

command of abstract mathematical theory together with a clear

insight into the structure of the system, and doubt not that the

instruction which accomplishes this is valuable and interesting

even if it neglects practical applications. If the instruction

sharpens the understanding, if it arouses the scientific

interest, whether mathematical or philosophical, if finally it

calls into life an esthetic feeling for the beauty of a

scientific edifice, the instruction will take on an ethical value

as well, provided that with the interest it awakens also the

impulse toward scientific activity. I contend, therefore, that

even without reference to its applications mathematics in the

high schools has a value equal to that of the other subjects of

instruction.--GOETTING, E.

_Ueber das Lehrziel im mathematischen

Unterricht der höheren Realanstalten;

Jahresbericht der Deutschen Mathematiker

Vereinigung, Bd. 2, p. 192._

=508.= Mathematics will not be properly esteemed in wider circles

until more than the _a b c_ of it is taught in the schools, and

until the unfortunate impression is gotten rid of that mathematics

serves no other purpose in instruction than the _formal_ training

of the mind. The aim of mathematics is its _content_, its form

is a secondary consideration and need not necessarily be that

historic form which is due to the circumstance that mathematics

took permanent shape under the influence of Greek logic.--HANKEL, H.

_Die Entwickelung der Mathematik in den

letzten Jahrhunderten (Tübingen, 1884),

p. 6._

=509.= The idea that aptitude for mathematics is rarer than

aptitude for other subjects is merely an illusion which is caused

by belated or neglected beginners.--HERBART, J. F.

_Umriss pädagogischer Vorlesungen; Werke

[Kehrbach] (Langensalza, 1902), Bd. 10,

p. 101._

=510.= I believe that the useful methods of mathematics are easily

to be learned by quite young persons, just as languages are easily

learned in youth. What a wondrous philosophy and history underlie

the use of almost every word in every language--yet the child

learns to use the word unconsciously. No doubt when such a word

was first invented it was studied over and lectured upon, just as

one might lecture now upon the idea of a rate, or the use of

Cartesian co-ordinates, and we may depend upon it that children of

the future will use the idea of the calculus, and use squared

paper as readily as they now cipher.... When Egyptian and Chaldean

philosophers spent years in difficult calculations, which would

now be thought easy by young children, doubtless they had the same

notions of the depth of their knowledge that Sir William Thomson

might now have of his. How is it, then, that Thomson gained his

immense knowledge in the time taken by a Chaldean philosopher to

acquire a simple knowledge of arithmetic? The reason is plain.

Thomson, when a child, was taught in a few years more than all

that was known three thousand years ago of the properties of

numbers. When it is found essential to a boy’s future that

machinery should be given to his brain, it is given to him; he is

taught to use it, and his bright memory makes the use of it a

second nature to him; but it is not till after-life that he makes

a close investigation of what there actually is in his brain which

has enabled him to do so much. It is taken because the child has

much faith. In after years he will accept nothing without careful

consideration. The machinery given to the brain of children is

getting more and more complicated as time goes on; but there is

really no reason why it should not be taken in as early, and used

as readily, as were the axioms of childish education in ancient

Chaldea.--PERRY, JOHN.

_The Teaching of Mathematics (London,

1902), p. 14._

=511.= The ancients devoted a lifetime to the study of

arithmetic; it required days to extract a square root or to

multiply two numbers together. Is there any harm in skipping all

that, in letting the school boy learn multiplication sums, and in

starting his more abstract reasoning at a more advanced point?

Where would be the harm in letting the boy assume the truth of

many propositions of the first four books of Euclid, letting him

assume their truth partly by faith, partly by trial? Giving him

the whole fifth book of Euclid by simple algebra? Letting him

assume the sixth as axiomatic? Letting him, in fact, begin his

severer studies where he is now in the habit of leaving off? We

do much less orthodox things. Every here and there in one’s

mathematical studies one makes exceedingly large assumptions,

because the methodical study would be ridiculous even in the eyes

of the most pedantic of teachers. I can imagine a whole year

devoted to the philosophical study of many things that a student

now takes in his stride without trouble. The present method of

training the mind of a mathematical teacher causes it to strain

at gnats and to swallow camels. Such gnats are most of the

propositions of the sixth book of Euclid; propositions generally

about incommensurables; the use of arithmetic in geometry; the

parallelogram of forces, etc., decimals.--PERRY, JOHN.

_The Teaching of Mathematics (London,

1904), p. 12._

=512.= The teaching of elementary mathematics should be conducted

so that the way should be prepared for the building upon them of

the higher mathematics. The teacher should always bear in mind

and look forward to what is to come after. The pupil should not

be taught what may be sufficient for the time, but will lead to

difficulties in the future.... I think the fault in teaching

arithmetic is that of not attending to general principles and

teaching instead of particular rules.... I am inclined to attack

the teaching of mathematics on the grounds that it does not dwell

sufficiently on a few general axiomatic principles.

--HUDSON, W. H. H.

_Perry’s Teaching of Mathematics

(London, 1904), p. 33._

=513.= “Mathematics in Prussia! Ah, sir, they teach mathematics

in Prussia as you teach your boys rowing in England: they are

trained by men who have been trained by men who have themselves

been trained for generations back.”--LANGLEY, E. M.

_Perry’s Teaching of Mathematics

(London, 1904), p. 43._

=514.= A superficial knowledge of mathematics may lead to the

belief that this subject can be taught incidentally, and that

exercises akin to counting the petals of flowers or the legs of a

grasshopper are mathematical. Such work ignores the fundamental

idea out of which quantitative reasoning grows--the equality of

magnitudes. It leaves the pupil unaware of that relativity which

is the essence of mathematical science. Numerical statements are

frequently required in the study of natural history, but to

repeat these as a drill upon numbers will scarcely lend charm to

these studies, and certainly will not result in mathematical

knowledge.--SPEER, W. W.

_Primary Arithmetic (Boston, 1897), pp.

26-27._

=515.= Mathematics is no more the art of reckoning and

computation than architecture is the art of making bricks or

hewing wood, no more than painting is the art of mixing colors on

a palette, no more than the science of geology is the art of

breaking rocks, or the science of anatomy the art of butchering.

--KEYSER, C. J.

_Lectures on Science, Philosophy and Art

(New York, 1908), p. 29._

=516.= The study of mathematics--from ordinary reckoning up to

the higher processes--must be connected with knowledge of nature,

and at the same time with experience, that it may enter the

pupil’s circle of thought.--HERBART, J. F.

_Letters and Lectures on Education

[Felkin] (London, 1908), p. 117._

=517.= First, as concerns the _success_ of teaching mathematics.

No instruction in the high schools is as difficult as that of

mathematics, since the large majority of students are at first

decidedly disinclined to be harnessed into the rigid framework of

logical conclusions. The interest of young people is won much

more easily, if sense-objects are made the starting point and the

transition to abstract formulation is brought about gradually.

For this reason it is psychologically quite correct to follow

this course.

Not less to be recommended is this course if we inquire into the

essential purpose of mathematical instruction. Formerly it was

too exclusively held that this purpose is to sharpen the

understanding. Surely another important end is to implant in the

student the conviction that _correct thinking based on true

premises secures mastery over the outer world_. To accomplish

this the outer world must receive its share of attention from the

very beginning.

Doubtless this is true but there is a danger which needs

pointing out. It is as in the case of language teaching where the

modern tendency is to secure in addition to grammar also an

understanding of the authors. The danger lies in grammar

being completely set aside leaving the subject without its

indispensable solid basis. Just so in the teaching of mathematics

it is possible to accumulate interesting applications to such an

extent as to stunt the essential logical development. This should

in no wise be permitted, for thus the kernel of the whole matter

is lost. Therefore: We do want throughout a quickening of

mathematical instruction by the introduction of applications, but

we do not want that the pendulum, which in former decades may

have inclined too much toward the abstract side, should now swing

to the other extreme; we would rather pursue the proper middle

course.--KLEIN, FELIX.

_Ueber den Mathematischen Unterricht an

den höheren Schulen; Jahresbericht der

Deutschen Mathematiker Vereinigung, Bd.

11, p. 131._

=518.= It is above all the duty of the methodical text-book to

adapt itself to the pupil’s power of comprehension, only

challenging his higher efforts with the increasing development

of his imagination, his logical power and the ability of

abstraction. This indeed constitutes a test of the art of

teaching, it is here where pedagogic tact becomes manifest. In

reference to the axioms, caution is necessary. It should be

pointed out comparatively early, in how far the mathematical body

differs from the material body. Furthermore, since mathematical

bodies are really portions of space, this space is to be

conceived as mathematical space and to be clearly distinguished

from real or physical space. Gradually the student will become

conscious that the portion of the real space which lies beyond

the visible stellar universe is not cognizable through the

senses, that we know nothing of its properties and consequently

have no basis for judgments concerning it. Mathematical space, on

the other hand, may be subjected to conditions, for instance, we

may condition its properties at infinity, and these conditions

constitute the axioms, say the Euclidean axioms. But every

student will require years before the conviction of the truth of

this last statement will force itself upon him.

--HOLZMÜLLER, GUSTAV.

_Methodisches Lehrbuch der

Elementar-Mathematik (Leipzig, 1904),

Teil 1, Vorwort, pp. 4-5._

=519.= Like almost every subject of human interest, this one

[mathematics] is just as easy or as difficult as we choose to

make it. A lifetime may be spent by a philosopher in discussing

the truth of the simplest axiom. The simplest fact as to our

existence may fill us with such wonder that our minds will remain

overwhelmed with wonder all the time. A Scotch ploughman makes a

working religion out of a system which appalls a mental

philosopher. Some boys of ten years of age study the methods of

the differential calculus; other much cleverer boys working at

mathematics to the age of nineteen have a difficulty in

comprehending the fundamental ideas of the calculus.--PERRY, JOHN.

_The Teaching of Mathematics (London,

1902), pp. 19-20._

=520.= Poor teaching leads to the inevitable idea that the

subject [mathematics] is only adapted to peculiar minds, when it

is the one universal science and the one whose four ground-rules

are taught us almost in infancy and reappear in the motions of

the universe.--SAFFORD, T. H.

_Mathematical Teaching (Boston, 1907),

p. 19._

=521.= The number of mathematical students ... would be much

augmented if those who hold the highest rank in science would

condescend to give more effective assistance in clearing the

elements of the difficulties which they present.--DE MORGAN, A.

_Study and Difficulties of Mathematics

(Chicago, 1902), Preface._

=522.= He that could teach mathematics well, would not be a bad

teacher in any of the rest [physics, chemistry, biology,

psychology] unless by the accident of total inaptitude for

experimental illustration; while the mere experimentalist is

likely to fall into the error of missing the essential condition

of science as reasoned truth; not to speak of the danger of

making the instruction an affair of sensation, glitter, or

pyrotechnic show.--BAIN, ALEXANDER.

_Education as a Science (New York,

1898), p. 298._

=523.= I should like to draw attention to the inexhaustible

variety of the problems and exercises which it [mathematics]

furnishes; these may be graduated to precisely the amount of

attainment which may be possessed, while yet retaining an

interest and value. It seems to me that no other branch of study

at all compares with mathematics in this. When we propose a

deduction to a beginner we give him an exercise in many cases

that would have been admired in the vigorous days of Greek

geometry. Although grammatical exercises are well suited to

insure the great benefits connected with the study of languages,

yet these exercises seem to me stiff and artificial in comparison

with the problems of mathematics. It is not absurd to maintain

that Euclid and Apollonius would have regarded with interest many

of the elegant deductions which are invented for the use of our

students in geometry; but it seems scarcely conceivable that the

great masters in any other line of study could condescend to give

a moment’s attention to the elementary books of the beginner.

--TODHUNTER, ISAAC.

_Conflict of Studies (London, 1873), pp.

10-11._

=524.= The visible figures by which principles are illustrated

should, so far as possible, have no accessories. They should be

magnitudes pure and simple, so that the thought of the pupil may

not be distracted, and that he may know what features of the

thing represented he is to pay attention to.

_Report of the Committee of Ten on

Secondary School Subjects, (New York,

1894), p. 109._

=525.= Geometrical reasoning, and arithmetical process, have each

its own office: to mix the two in elementary instruction, is

injurious to the proper acquisition of both.--DE MORGAN, A.

_Trigonometry and Double Algebra

(London, 1849), p. 92._

=526.= Equations are Expressions of Arithmetical Computation, and

properly have no place in Geometry, except as far as Quantities truly

Geometrical (that is, Lines, Surfaces, Solids, and Proportions) may

be said to be some equal to others. Multiplications, Divisions, and

such sort of Computations, are newly received into Geometry, and that

unwarily, and contrary to the first Design of this Science. For

whosoever considers the Construction of a Problem by a right Line

and a Circle, found out by the first Geometricians, will easily

perceive that Geometry was invented that we might expeditiously

avoid, by drawing Lines, the Tediousness of Computation. Therefore

these two Sciences ought not to be confounded. The Ancients did so

industriously distinguish them from one another, that they never

introduced Arithmetical Terms into Geometry. And the Moderns,

by confounding both, have lost the Simplicity in which all the

Elegance of Geometry consists. Wherefore that is _Arithmetically_

more simple which is determined by the more simple Equation, but

that is _Geometrically_ more simple which is determined by the

more simple drawing of Lines; and in Geometry, that ought to be

reckoned best which is geometrically most simple.--NEWTON.

_On the Linear Construction of

Equations; Universal Arithmetic (London,

1769), Vol. 2, p. 470._

=527.= As long as algebra and geometry proceeded along separate

paths, their advance was slow and their applications limited.

But when these sciences joined company, they drew from each other

fresh vitality and thenceforward marched on at a rapid pace

toward perfection.--LAGRANGE.

_Leçons Élémentaires sur les

Mathematiques, Leçon cinquiéme.

[McCormack]._

=528.= The greatest enemy to true arithmetic work is found in

so-called practical or illustrative problems, which are freely

given to our pupils, of a degree of difficulty and complexity

altogether unsuited to their age and mental development.... I am,

myself, no bad mathematician, and all the reasoning powers with

which nature endowed me have long been as fully developed as they

are ever likely to be; but I have, not infrequently, been

puzzled, and at times foiled, by the subtle logical difficulty

running through one of these problems, given to my own children.

The head-master of one of our Boston high schools confessed to me

that he had sometimes been unable to unravel one of these tangled

skeins, in trying to help his own daughter through her evening’s

work. During this summer, Dr. Fairbairn, the distinguished head

of one of the colleges of Oxford, England, told me that not only

had he himself encountered a similar difficulty, in the case of

his own children, but that, on one occasion, having as his guest

one of the first mathematicians of England, the two together had

been completely puzzled by one of these arithmetical conundrums.

--WALKER, F. A.

_Discussions in Education (New York,

1899), pp. 253-254._

=529.= It is often assumed that because the young child is not

competent to study geometry systematically he need be taught

nothing geometrical; that because it would be foolish to present

to him physics and mechanics as sciences it is useless to present

to him any physical or mechanical principles.

An error of like origin, which has wrought incalculable mischief,

denies to the scholar the use of the symbols and methods of

algebra in connection with his early essays in numbers because,

forsooth, he is not as yet capable of mastering quadratics!...

The whole infant generation, wrestling with arithmetic, seek for

a sign and groan and travail together in pain for the want of it;

but no sign is given them save the sign of the prophet Jonah,

_the withered gourd_, fruitless endeavor, wasted strength.

--WALKER, F. A.

_Industrial Education; Discussions in

Education (New York, 1899), p. 132._

=530.= Particular and contingent inventions in the solution of

problems, which, though many times more concise than a general

method would allow, yet, in my judgment, are less proper to

instruct a learner, as acrostics, and such kind of artificial

poetry, though never so excellent, would be but improper examples

to instruct one that aims at Ovidean poetry.--NEWTON, ISAAC.

_Letter to Collins, 1670; Macclesfield,

Correspondence of Scientific Men

(Oxford, 1841), Vol. 2, p. 307._

=531.= The logic of the subject [algebra], which, both educationally

and scientifically speaking, is the most important part of it, is

wholly neglected. The whole training consists in example grinding.

What should have been merely the help to attain the end has become

the end itself. The result is that algebra, as we teach it, is

neither an art nor a science, but an ill-digested farrago of rules,

whose object is the solution of examination problems.... The

result, so far as problems worked in examinations go, is, after

all, very miserable, as the reiterated complaints of examiners

show; the effect on the examinee is a well-known enervation of

mind, an almost incurable superficiality, which might be called

Problematic Paralysis--a disease which unfits a man to follow an

argument extending beyond the length of a printed octavo page.

--CHRYSTAL, GEORGE.

_Presidential Address British

Association for the Advancement of

Science, 1885; Nature, Vol. 32, pp.

447-448._

=532.= It is a serious question whether America, following

England’s lead, has not gone into problem-solving too extensively.

Certain it is that we are producing no text-books in which the

theory is presented in the delightful style which characterizes

many of the French works ..., or those of the recent Italian

school, or, indeed, those of the continental writers in general.

--SMITH, D. E.

_The Teaching of Elementary Mathematics

(New York, 1902), p. 219._

=533.= The problem for a writer of a text-book has come now, in

fact, to be this--to write a book so neatly trimmed and compacted

that no coach, on looking through it, can mark a single passage

which the candidate for a minimum pass can safely omit. Some of

these text-books I have seen, where the scientific matter has

been, like the lady’s waist in the nursery song, compressed “so

gent and sma’,” that the thickness barely, if at all, surpasses

what is devoted to the publisher’s advertisements. We shall

return, I verily believe, to the Compendium of Martianus Capella.

The result of all this is that science, in the hands of

specialists, soars higher and higher into the light of day, while

educators and the educated are left more and more to wander in

primeval darkness.--CHRYSTAL, GEORGE.

_Presidential Address British

Association for the Advancement of

Science, 1885; Nature, Vol. 32, p. 448._

=534.= Some persons have contended that mathematics ought to be

taught by making the illustrations obvious to the senses. Nothing

can be more absurd or injurious: it ought to be our never-ceasing

effort to make people think, not feel.--COLERIDGE, S. T.

_Lectures on Shakespere (Bohn Library),

p. 52._

=535.= I have come to the conclusion that the exertion, without

which a knowledge of mathematics cannot be acquired, is not

materially increased by logical rigor in the method of instruction.

--PRINGSHEIM, ALFRED.

_Jahresbericht der Deutschen

Mathematiker Vereinigung (1898), p.

143._

=536.= The only way in which to treat the elements of an exact

and rigorous science is to apply to them all the rigor and

exactness possible.--D’ALEMBERT.

_Quoted by De Morgan: Trigonometry and

Double Algebra (London, 1849), Title

page._

=537.= It is an error to believe that rigor in proof is an enemy

of simplicity. On the contrary we find it confirmed by numerous

examples that the rigorous method is at the same time the simpler

and the more easily comprehended. The very effort for rigor

forces us to find out simpler methods of proof.--HILBERT, D.

_Mathematical Problems; Bulletin

American Mathematical Society, Vol. 8,

p. 441._

=538.= Few will deny that even in the first scientific instruction

in mathematics the most rigorous method is to be given preference

over all others. Especially will every teacher prefer a consistent

proof to one which is based on fallacies or proceeds in a vicious

circle, indeed it will be morally impossible for the teacher to

present a proof of the latter kind consciously and thus in a sense

deceive his pupils. Notwithstanding these objectionable so-called

proofs, so far as the foundation and the development of the system

is concerned, predominate in our textbooks to the present time.

Perhaps it will be answered, that rigorous proof is found too

difficult for the pupil’s power of comprehension. Should this be

anywhere the case,--which would only indicate some defect in the

plan or treatment of the whole,--the only remedy would be to

merely state the theorem in a historic way, and forego a proof

with the frank confession that no proof has been found which could

be comprehended by the pupil; a remedy which is ever doubtful and

should only be applied in the case of extreme necessity. But this

remedy is to be preferred to a proof which is no proof, and is

therefore either wholly unintelligible to the pupil, or deceives

him with an appearance of knowledge which opens the door to all

superficiality and lack of scientific method.--GRASSMANN, HERMANN.

_Stücke aus dem Lehrbuche der

Arithmetik; Werke, Bd. 2 (Leipsig,

1904), p. 296._

=539.= The average English author [of mathematical texts] leaves

one under the impression that he has made a bargain with his

reader to put before him the truth, the greater part of the

truth, and nothing but the truth; and that if he has put the

facts of his subject into his book, however difficult it may be

to unearth them, he has fulfilled his contract with his reader.

This is a very much mistaken view, because _effective teaching_

requires a great deal more than a bare recitation of facts, even

if these are duly set forth in logical order--as in English books

they often are not. The probable difficulties which will occur to

the student, the objections which the intelligent student will

naturally and necessarily raise to some statement of fact or

theory--these things our authors seldom or never notice, and yet

a recognition and anticipation of them by the author would be

often of priceless value to the student. Again, a touch of

_humour_ (strange as the contention may seem) in mathematical

works is not only possible with perfect propriety, but very

helpful; and I could give instances of this even from the pure

mathematics of Salmon and the physics of Clerk Maxwell.

--MINCHIN, G. M.

_Perry’s Teaching of Mathematics

(London, 1902), pp. 59-61._

=540.= Remember this, the rule for giving an extempore lecture

is--let the mind rest from the subject entirely for an interval

preceding the lecture, after the notes are prepared; the thoughts

will ferment without your knowing it, and enter into new

combinations; but if you keep the mind active upon the subject up

to the moment, the subject will not ferment but stupefy.

--DE MORGAN, A.

_Letter to Hamilton; Graves: Life of W.

R. Hamilton (New York, 1882-1889), Vol.

3, p. 487._

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