Population

POPULATION. - It is the aggregate of all the inhabitants of a country, of a region, of 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). Therefore it can be determined quantitatively and qualitatively if it is circumscribed in space, in time and in its normal conditions. The p. can be considered under various aspects and, first of all, in its absolute size or mass, in its relative size or density, in its growth.

I. THE ABSOLUTE SIZE OF THE POPULATION

The absolute size of the population is determined through that complex of operations known as a census: at a given moment on a given day, the organ of the State expressly charged by law with this task proceeds to enumerate all the persons present throughout the entire territory of the State itself by means of special forms, called household schedules (for family units) and institutional schedules (for non-family units, such as hotels, barracks, convents, colleges, etc.). The totality of persons who at the moment of the census are within the territory of the State constitutes the so-called present or de facto population. In Italy, on 4 Nov. 1951 (the last general census) the present or de facto population was found to be 46,737,704 persons. It differs, however, from the resident population, the latter being constituted by the totality of persons who have their dwelling in a given administrative district (Comune), some of whom may also be absent at the moment of the census, because they are in another Comune or even outside the territory of the State. The size of the resident population, therefore, is obtained by adding to the total of those present the number of persons temporarily absent, and subtracting the number of persons temporarily present who do not have their dwelling in the Comune. The size of the resident population, according to current provisions, is taken in Italy as the legal population until such time as another census is carried out. In Italy, on 4 Nov. 1951, according to the first results of the last census, the resident population was found to be 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, constituting the normal point of reference in the study of social phenomena, but also practically, since it constitutes the basis of the political and administrative organization of the State, for whose purposes the resident population is taken as legal. In Italy, for example, it is on the basis of the number of inhabitants of the Comuni and the provinces that the number of municipal councillors and assessors is determined, the rates for certain local taxes (family tax, rental value), the number of notaries, the number of State monopolies, etc. Also in international relations, frequently, knowledge of the size of the population of the various countries constitutes a requirement of undisputed importance. However, not for all countries are reliable data available on the absolute number of inhabitants; in many of them no censuses are carried out and the number of inhabitants is given by estimates based on statistical indications. It is indeed to such estimates that demographers have had to resort in order to determine the population of the world and of its major divisions. In 1935 it was estimated at around 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 beyond the absolute size of the population, it is also important to know its structure, that is, its composition by sex, age, marital status, profession or occupational status, etc. Its composition by sex is relatively constant in time and space, except in countries with a strong migratory movement of persons of the same sex; for the most part the number of females slightly exceeds that of males as a result of the higher mortality of the latter. This is so, for example, in the European countries. In America, Australia and New Zealand, a slight male predominance is found, plausibly caused by immigration. Variations upward or downward, due in large part to migratory movements or to other social phenomena, may also occur over the course of time. Thus in Italy, at the census of 1881 a very slight male predominance was found (1005 males for every 1000 females), whereas in 1936 the ratio was 943 males per 1000 females.

Far more variable, however, both in time and in space, are the other characteristics (age, marital status, profession or status). The distribution of the population by age is extremely variable from country to country and, within the same country, from one period to another. It is estimated that in 1940 the population under 15 years of age was 29.6% in Italy, 23.7% in France, 21.6% in Germany, 36.2% in the U.S.S.R. Rather notable differences are also found with regard to marital status. The proportion of single, married, widowed, separated and divorced persons varies considerably from country to country; where the institution of divorce is permitted, the proportion of divorced persons (even excluding those who have entered into new marriages) proves quite different depending on the greater or lesser ease with which the law permits the dissolution of marriage. Even more profound are the differences from country to country with regard to profession or status and, within the same country, from one region to another. According to the results of a survey, in the provinces of Sicily, persons in non-professional status constituted 67% of the total, whereas in the province of Milan 52%. The very proportion of the various professions proves to be linked to the economic and social conditions of the country and the region: where agriculture predominates, agricultural professions predominate, and so on.

II. THE DENSITY OF THE POPULATION

Besides the absolute size of the population, it is also important to know the 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 kilometer. In this regard, however, when making comparisons between states, or even between smaller administrative divisions, one must bear in mind that the habitable part of the territory, or ecumene, is extremely variable. In Italy, the density of the population, which at the date of 1936 was 139.6, rose according to the census of Nov. 4, 1951 to 154.3. It is, however, quite different from region to region; higher in Campania (314), in Liguria (282), in Lombardy (263), in Venetia (210), in Latium

(200); lower in Sardinia (50), Basilicata (62), Umbria (94). According to the estimates made by demographers, the density of the population 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 divisions a distinction is made between concentrated population, that is, residing in the centers, and dispersed population; between urban population, that is, residing in cities, and rural population.

III. GROWTH OF THE POPULATION

As was mentioned at the beginning, the size and composition of the population changes incessantly from one moment to the next, as a result of births and deaths (natural movement) and of migrations (social movement). The study of these movements is therefore of particular importance, since it is on their intensity and direction that the variations in the composition and size of the population depend. These movements are recorded, for births and deaths, by registry records. The difference between the number of births and the number of deaths in a given interval of time constitutes the natural increase in that given interval. To it must be added or subtracted the social increase or decrease, or the difference between emigrants and immigrants. The growth of the population is determined, at longer intervals, by means of censuses. Of this increase one can give both the absolute and the relative measure. A relative measure is given by the average annual rate of growth, which demographers assimilate to that of a sum invested at compound interest, where the population at the initial moment constitutes the capital and that at the end of the period considered the amount. It is quite evident that the various factors mentioned above contribute to the growth of the population, both in an absolute and in a relative sense, in proportions altogether different from country to country and, in the same country, from one period to another. Such analysis constitutes the particular province of demography (v.).

IV. THEORIES ON THE POPULATION

The study of the factors determining the increase of the population has long fascinated demographers and sociologists. The founder of demography himself, J. Graunt, alludes (1662) to a tendency toward the growth of the population. Later A. Petty (1682) deals on purpose with the interesting subject, and puts forward the hypothesis that the population has a tendency to double in the space of about 200 years. Later the German Protestant pastor G. P. Süssmilch (1707-67) in his work entitled The Divine Order in the Changes of the Human Race (1741) notes that the population tends to multiply through the excess of births over deaths, and it would double at equal intervals if the increase of inhabitants were accompanied by a proportional increase in the means of subsistence. The question is taken up again by G. Ortes (1775), who maintains that the population would tend to multiply geometrically every 30 years, if the action of various economic and social factors did not halt this tendency. Thus we come to 1798, when Thomas Robert Malthus (v.) with the work entitled Essay on the Principle of Population formulated that theory which was to have such resonance and to which he has linked his fame. From Malthus's theory there subsequently arose the so-called neo-Malthusian movement (v. NEO-MALTHUSIANISM).

Carmelo D'Agata