Population

POPULATION. — It is the totality of all the inhabitants of a country, a region, a city, etc. Its size and composition vary incessantly as a result of births and deaths (natural movement) and, within a given area, also as a result of migrations (social movement). It can therefore be determined quantitatively and qualitatively when delimited in space, time, and its normal conditions. Population may be considered from various aspects, first of all in its absolute size or mass, its relative size or density, and its growth.

I. THE ABSOLUTE SIZE OF THE P

The absolute size of the p. is determined through the set of operations known as a census: at a given moment on a specified day, the State organ expressly appointed by law for this purpose proceeds to enumerate all the persons found throughout the territory of the State by means of special forms, called family sheets (for family units) and communal-living sheets (for non-family units, such as hotels, barracks, convents, boarding schools, etc.). The total number of persons found in the territory of the State at the time of the census constitutes the so-called present or de facto p. In Italy, on 4 Nov. 1951 (the date of the latest general census), the present or de facto p. amounted to 46,737,704 persons. This differs, however, from the resident p., which consists of the total number of persons having their domicile in a given administrative district (Comune), some of whom may be absent at the time of the census because they are in another Comune or even outside the territory of the State. The size of the resident p. is therefore obtained by adding to the total number present the number of persons temporarily absent, and subtracting the number of persons temporarily present who do not have their domicile in the Comune. In Italy, under the regulations currently in force, the size of the resident p. is regarded as the legal p. until another census is carried out. In Italy, on 4 Nov. 1951, according to the preliminary results of the latest census, the resident p. amounted to 47,138,235, of whom 23,085,776 were males and 24,052,459 females.

Knowledge of the number of inhabitants is of great importance not only scientifically, since it constitutes the normal point of reference in the study of social phenomena, but also practically, since it forms the basis of the political and administrative organization of the State, for whose purposes the resident p. is adopted as the legal figure. In Italy, for example, the number of municipal councillors and assessors, the rates for certain local taxes (the family tax, rental value), the number of notaries, the number of State monopolies, etc., are determined on the basis of the number of inhabitants of the Comuni and provinces. In international relations, too, knowledge of the size of the p. of the various countries is often an undeniably important requirement. However, reliable data on the absolute number of inhabitants are not available for all countries; in many of them censuses are not carried out, and the number of inhabitants is given through estimates based on statistical indications. Demographers have in fact had to resort to such estimates in determining the p. of the world and its principal divisions. In 1935 it was estimated at approximately 2,076 million, of whom 524 million were in Europe, 261 in America, 10 in Oceania, 145 in Africa, and 1,136 in Asia.

But in addition to the absolute size of the p., it is also important to know its structure, that is, its composition by sex, age, marital status, occupation or occupational status, etc. Its composition by sex is relatively constant over time and space, except in countries experiencing strong migratory movements of persons of the same sex; for the most part, the number of females slightly exceeds that of males as a result of the latter’s higher mortality. This is the case, for example, in the European countries. In America, Australia, and New Zealand, a slight male predominance is found, plausibly caused by immigration. Increases or decreases, due largely to migratory movements or other social phenomena, may also occur over time. Thus, in Italy, the 1881 census showed a very slight male predominance (1,005 males for every 1,000 females), whereas in 1936 the ratio was 943 males to 1,000 females.

The other characteristics (age, marital status, occupation or condition), however, are much more variable, both over time and in space. The age distribution of the p. varies greatly from one country to another and, within the same country, from one period to another. It is estimated that in 1940 the p. under 15 years of age amounted to 29.6% in Italy, 23.7% in France, 21.6% in Germany, and 36.2% in the U.S.S.R. Quite considerable differences are also found with regard to marital status. The proportion of single, married, widowed, separated, and divorced persons varies greatly from one country to another; where divorce is legally recognized, the proportion of divorced persons (even excluding those who have subsequently remarried) varies considerably according to the greater or lesser ease with which the law permits the dissolution of marriage. The differences from one country to another with regard to occupation or condition, and within the same country from one region to another, are even more pronounced. According to the results of a survey, in the provinces of Sicily persons in non-occupational conditions constituted 67% of the total, whereas in the province of Milan they constituted 52%. The proportion of the various occupations is likewise linked to the economic and social conditions of the country and region: wherever agriculture predominates, agricultural occupations predominate, and so forth.

II. THE DENSITY OF THE P

In addition to the absolute size of the p., it is also important to know its relative size, or density. This is obtained from the ratio between the absolute size and the area, and the quotient expresses the number of inhabitants per square kilometre. In this regard, however, when making comparisons between States, or even between smaller administrative districts, it is necessary to take into account that the habitable part of the territory, or ecumene, varies enormously. In Italy, the density of the p., which in 1936 was 139.6, rose, according to the census of 4 November 1951, to 154.3. It is, however, highly dissimilar from one region to another: higher in Campania (314), Liguria (282), Lombardy (263), Veneto (210), Lazio

(200); lower in Sardinia (50), Basilicata (62), Umbria (94). According to estimates made by demographers, the density of the p. in the various continents, around 1935, was as follows: Europe 45.9; America 6.4, Oceania 1.2, Africa 4.8, Asia 27.1. Within smaller administrative districts, a distinction is made between concentrated p., that is, residing in population centres, and scattered p.; between urban p., that is, residing in cities, and rural p.

III. GROWTH OF THE p

As was mentioned at the outset, the size and composition of the p. vary incessantly from one moment to the next, as a result of births and deaths (natural movement) and migrations (social movement). The study of these movements is therefore of particular importance, since variations in the composition and size of the p. depend on their intensity and direction. These movements are recorded, in the case of births and deaths, by civil-register records. The difference between the number of births and the number of deaths in a given period constitutes the natural increase during that period. To this must be added or subtracted the social increase or decrease, that is, the difference between emigrants and immigrants. The growth of the p. is determined, at longer intervals, by means of censuses. This increase can be expressed both in absolute and in relative terms. A relative measure is provided by the average annual rate of growth, which demographers compare to that of a sum invested at compound interest, with the p. at the initial moment constituting the capital and that at the end of the period under consideration the accrued amount. It is quite evident that the growth of the p., both in absolute and relative terms, is determined by the various factors mentioned above, in proportions that differ entirely from country to country and, within the same country, from one period to another. This analysis constitutes a demography (v.).

IV. THEORIES CONCERNING THE POPULATION

The study of the factors determining population growth has long engaged demographers and sociologists. The very founder of demography, J. Graunt, already pointed (1662) to a tendency toward population growth. Later, A. Petty (1682) addressed the interesting subject specifically, and advanced the hypothesis that the population tended to double in approximately 200 years. Later still, the German Protestant pastor G. P. Slassmich (1707–67), in his work entitled L'ordine divino nei mutamenti del genere umano (1741), observed that the population tended to multiply as a result of births exceeding deaths, and that it would double at equal intervals if an increase in the inhabitants were accompanied by a proportional increase in the means of subsistence. The question was taken up again by G. Ortes (1775), who maintained that the population would tend to increase geometrically every 30 years if the action of various economic and social factors did not halt this tendency. Thus we come to 1798, MALTHUS, THOMAS ROBERT (v.) formulated, in his work entitled Saggio sul principio della p., the theory that was to achieve such wide resonance and to which he owed his fame. The so-called neo-Malthusian movement (v. NEO-MALTHUSIANESIMO) subsequently arose from Malthus’s theory.