Principles of Economics by Alfred Marshall 马歇尔的经济学原理(英文版) txt+doc+PDF+MP3 解压密码和word文档的打开密码为:alfredmarshall
Principles of Economics
Alfred Marshall
Principles of Economics
An Introductory Volume
Natura non facit saltum
PREFACE TO THE FIRST EDITION.
Economic conditions are constantly changing, and each generation looks at its
own problems in its own way. In England, as well as on the Continent and in
America, Economic studies are being more vigorously pursued now than ever
before; but all this activity has only shown the more clearly that Economic
science is, and must be, one of slow and continuous growth. Some of the best
work of the present generation has indeed appeared at first sight to be
antagonistic to that of earlier writers; but when it has had time to settle down
into its proper place, and its rough edges have been worn away, it has been
found to involve no real breach of continuity in the development of the science.
The new doctrines have supplemented the older, have extended, developed, and
sometimes corrected them, and often have given them a different tone by a new
distribution of emphasis; but very seldom have subverted them.
P.1
The present treatise is an attempt to present a modern version of old doctrines
with the aid of the new work, and with reference to the new problems, of our
own age. Its general scope and purpose are indicated in Book I.; at the end of
which a short account is given of what are taken to be the chief subjects of
economic inquiry, and the chief practical issues on which that inquiry has a
bearing. In accordance with English traditions, it is held that the function of the
science is to collect, arrange and analyse economic facts, and to apply the
knowledge, gained by observation and experience, in determining what are
likely to be the immediate and ultimate effects of various groups of causes; and
it is held that the Laws of Economics are statements of tendencies expressed in
the indicative mood, and not ethical precepts in the imperative. Economic laws
and reasonings in fact are merely a part of the material which Conscience and
Common-sense have to turn to account in solving practical problems, and in
laying down rules which may be a guide in life.
P.2
But ethical forces are among those of which the economist has to take account.
Attempts have indeed been made to construct an abstract science with regard to
the actions of an "economic man," who is under no ethical influences and who
pursues pecuniary gain warily and energetically, but mechanically and selfishly.
But they have not been successful, nor even thoroughly carried out. For they
have never really treated the economic man as perfectly selfish: no one could be
relied on better to endure toil and sacrifice with the unselfish desire to make
provision for his family; and his normal motives have always been tacitly
P.3 assumed to include the family affections. But if they include these, why should
they not include all other altruistic motives the action of which is so far uniform
in any class at any time and place, that it can be reduced to general rule? There
seems to be no reason; and in the present book normal action is taken to be that
which may be expected, under certain conditions, from the members of an
industrial group; and no attempt is made to exclude the influence of any
motives, the action of which is regular, merely because they are altruistic. If the
book has any special character of its own, that may perhaps be said to lie in the
prominence which it gives to this and other applications of the Principle of
Continuity.
This principle is applied not only to the ethical quality of the motives by which
a man may be influenced in choosing his ends, but also to the sagacity, the
energy and the enterprise with which he pursues those ends. Thus stress is laid
on the fact that there is a continuous gradation from the actions of "city men,"
which are based on deliberate and far-reaching calculations, and are executed
with vigour and ability, to those of ordinary people who have neither the power
nor the will to conduct their affairs in a business-like way. The normal
willingness to save, the normal willingness to undergo a certain exertion for a
certain pecuniary reward, or the normal alertness to seek the best markets in
which to buy and sell, or to search out the most advantageous occupation for
oneself or for one's children—all these and similar phrases must be relative to
the members of a particular class at a given place and time: but, when that is
once understood, the theory of normal value is applicable to the actions of the
unbusiness-like classes in the same way, though not with the same precision of
detail, as to those of the merchant or banker.
P.4
And as there is no sharp line of division between conduct which is normal, and
that which has to be provisionally neglected as abnormal, so there is none
between normal values and "current" or "market" or "occasional" values. The
latter are those values in which the accidents of the moment exert a
preponderating influence; while normal values are those which would be
ultimately attained, if the economic conditions under view had time to work out
undisturbed their full effect. But there is no impassable gulf between these two;
they shade into one another by continuous gradations. The values which we
may regard as normal if we are thinking of the changes from hour to hour on a
Produce Exchange, do but indicate current variations with regard to the year's
history: and the normal values with reference to the year's history are but
current values with reference to the history of the century. For the element of
Time, which is the centre of the chief difficulty of almost every economic
problem, is itself absolutely continuous: Nature knows no absolute partition of
time into long periods and short; but the two shade into one another by
imperceptible gradations, and what is a short period for one problem, is a long
period for another.
Thus for instance the greater part, though not the whole, of the distinction
between Rent and Interest on capital turns on the length of the period which we
have in view. That which is rightly regarded as interest on "free" or "floating"
capital, or on new investments of capital, is more properly treated as a sort of
P.6 rent—a Quasi-rent it is called below—on old investments of capital. And there
is no sharp line of division between floating capital and that which has been
"sunk" for a special branch of production, nor between new and old investments
of capital; each group shades into the other gradually. And thus even the rent of
land is seen, not as a thing by itself, but as the leading species of a large genus;
though indeed it has peculiarities of its own which are of vital importance from
the point of view of theory as well as of practice.
Again, though there is a sharp line of division between man himself and the
appliances which he uses; and though the supply of, and the demand for, human
efforts and sacrifices have peculiarities of their own, which do not attach to the
supply of, and the demand for, material goods; yet, after all, these material
goods are themselves generally the result of human efforts and sacrifices. The
theories of the values of labour, and of the things made by it, cannot be
separated: they are parts of one great whole; and what differences there are
between them even in matters of detail, turn out on inquiry to be, for the most
part, differences of degree rather than of kind. As, in spite of the great
differences in form between birds and quadrupeds, there is one Fundamental
Idea running through all their frames, so the general theory of the equilibrium of
demand and supply is a Fundamental Idea running through the frames of all the
various parts of the central problem of Distribution and Exchange*1
.
P.7
Another application of the Principle of Continuity is to the use of terms. There
has always been a temptation to classify economic goods in clearly defined
groups, about which a number of short and sharp propositions could be made, to
gratify at once the student's desire for logical precision, and the popular liking
for dogmas that have the air of being profound and are yet easily handled. But
great mischief seems to have been done by yielding to this temptation, and
drawing broad artificial lines of division where Nature has made none. The
more simple and absolute an economic doctrine is, the greater will be the
confusion which it brings into attempts to apply economic doctrines to practice,
if the dividing lines to which it refers cannot be found in real life. There is not in
real life a clear line of division between things that are and are not Capital, or
that are and are not Necessaries, or again between labour that is and is not
Productive.
P.8 The notion of continuity with regard to development is common to all modern
schools of economic thought, whether the chief influences acting on them are
those of biology, as represented by the writings of Herbert Spencer; or of
history and philosophy, as represented by Hegel's Philosophy of History, and by
more recent ethico-historical studies on the Continent and elsewhere. These two
kinds of influences have affected, more than any other, the substance of the
views expressed in the present book; but their form has been most affected by
mathematical conceptions of continuity, as represented in Cournot's Principes
Mathématiques de la Théorie des Richesses. He taught that it is necessary to
face the difficulty of regarding the various elements of an economic problem,—
not as determining one another in a chain of causation, A determining B, B
determining C, and so on—but as all mutually determining one another.
Nature's action is complex: and nothing is gained in the long run by pretending
that it is simple, and trying to describe it in a series of elementary propositions.
P.9
Under the guidance of Cournot, and in a less degree of von Thünen, I was led to
attach great importance to the fact that our observations of nature, in the moral
as in the physical world, relate not so much to aggregate quantities, as to
increments of quantities, and that in particular the demand for a thing is a
continuous function, of which the "marginal
*2
" increment is, in stable
equilibrium, balanced against the corresponding increment of its cost of
production. It is not easy to get a clear full view of continuity in this aspect
without the aid either of mathematical symbols or of diagrams. The use of the
latter requires no special knowledge, and they often express the conditions of
economic life more accurately, as well as more easily, than do mathematical
symbols; and therefore they have been applied as supplementary illustrations in
the footnotes of the present volume. The argument in the text is never dependent
on them; and they may be omitted; but experience seems to show that they give
a firmer grasp of many important principles than can be got without their aid;
and that there are many problems of pure theory, which no one who has once
learnt to use diagrams will willingly handle in any other way.
P.10
The chief use of pure mathematics in economic questions seems to be in helping
a person to write down quickly, shortly and exactly, some of his thoughts for his
own use: and to make sure that he has enough, and only enough, premisses for
his conclusions (i.e. that his equations are neither more nor less in number than
his unknowns). But when a great many symbols have to be used, they become
very laborious to any one but the writer himself. And though Cournot's genius
must give a new mental activity to everyone who passes through his hands, and
mathematicians of calibre similar to his may use their favourite weapons in
clearing a way for themselves to the centre of some of those difficult problems
of economic theory, of which only the outer fringe has yet been touched; yet it
seems doubtful whether any one spends his time well in reading lengthy
translations of economic doctrines into mathematics, that have not been made
by himself. A few specimens of those applications of mathematical language
which have proved most useful for my own purposes have, however, been
added in an Appendix.
September, 1890.