Change comes from two sources. One source is random or unique factors such as climate, weather, or the presence of specific groups of people. Another source is systematic factors. For example, successful development has the same general requirements, such as a stable and flexible government, enough free and available resources, and a diverse social organization of society. On the whole, social change is usually a combination of systematic factors along with some random or unique factors.
There are many theories of social change. Generally, a theory of change should include elements such as structural aspects of change (like population shifts), processes and mechanisms of social change, and directions of change.
Hegelian: The classic Hegelian dialectic model of change is based on the interaction of opposing forces. Starting from a point of momentary stasis, Thesis countered by Antithesis first yields conflict, then it subsequently results in a new Synthesis.
Marxist: Marxism presents a dialectical and materialist concept of history; Humankind's history is a fundamental struggle between social classes.
Heraclitan: The Greek philosopher Heraclitus used the metaphor of a river to speak of change thus, "On those stepping into rivers staying the same other and other waters flow" (DK22B12). What Heraclitus seems to be suggesting here, later interpretations notwithstanding, is that, in order for the river to remain the river, change must constantly be taking place. Thus one may think of the Heraclitan model as parallel to that of a living organism, which, in order to remain alive, must constantly be changing. A contemporary application of this approach is shown in the social change theory SEED-SCALE which builds off of the complexity theory subfield of Emergence.
Daoist: The Chinese philosophical work Dao De Jing, I.8 and II.78 uses the metaphor of water as the ideal agent of change. Water, although soft and yielding, will eventually wear away stone. Change in this model is to be natural, harmonious and steady, albeit imperceptible.
Current social changes
Global demographic shifts
One of the most obvious changes currently occurring is the change in the relative global population distribution between countries. In the recent decades, developing countries became a larger proportion of world population, increasing from 68% in 1950 to 82% in 2010, while population of the developed countries has declined from 32% of total world population in 1950 to 18% in 2010. China and India continue to be the largest countries, followed by the US as a distant third. However, population growth throughout the world is slowing. Population growth among developed countries has been slowing since the 1950s, and is now at 0.3% annual growth. Population growth among the less developed countries excluding the least developed has also been slowing, since 1960, and is now at 1.3% annual growth. Population growth among the least developed countries has slowed relatively little, and is the highest at 2.7% annual growth.
Gendered patterns of work and care
In much of the developed world, changes from distinct men's work and women's work to more gender equal patterns have been economically important since the mid-20th century. Both men and women are considered to be great contributors to social change worldwide.
Tilly, Charles. (1988). "Misreading, then Rereading, Nineteenth-Century Social Change." Pp. 332-58 in Social Structures: A Network Approach, eds. Barry Wellman and S.D. Berkowitz. Cambridge: Cambridge University Press.