For at least two centuries, population researchers have sought to explain longterm demographic trends. Some examples of these efforts are described in the works of S. Greenhalgh, D. van de Kaa, B. de Bruijn, and H. Leridon. In the Soviet Union, and, later, in Russia, the theory of demographic transition became, for some time, perhaps, the most influential theory, largely due to its impressive presentation to local readers by A. Vishnevsky. Later, this approach and some of the theory’s propositions were challenged by M. Klupt. The ensuing discussion between these scholars highlighted important aspects of demographic theories, their validity, and their usefulness. This article analyzes the debate with the goal of advancing demographic theories and fostering further research. The author employs several epistemological approaches to identify the best ways to assess the relevance of demographic theories.

demographic transition, institutionalism

The debate between supporters of the demographic transition theory and institutionally oriented scholars in the field of demographic studies has been ongoing for quite some time. A proponent of the first approach, A. Vishnevsky, has provided a consistent explanation of the first theory in Russian demographic literature through several influential works [Vishnevsky, 1985; 2005a]. The validity of the transition theory has been significantly challenged by another researcher, M. Klupt. His arguments against the relevance of the demographic transition theory were based on assumptions, borrowed from the institutional theory of fertility. Drawing on this theory, Klupt [2008] provided numerous empirical examples, aimed at demonstrating the appropriateness of using its assumptions to explain demographic dynamics and, consequently, attempted to refute the fundamental principles of the demographic transition theory. This disagreement later led to an exchange of several papers between the two authors, where they presented arguments in favor of their respective theories and counterarguments against the opposing theory [Vishnevsky 2005, 2012, 2014, 2015, 2017; Klupt 2012, 2014, 2015, 2018]. This stimulating discussion invites further elaboration on the still puzzling aspects of demographic developments worldwide, and encourages the development of optimal strategies for investigating them.

Before turning to the discussion of the arguments presented by both scholars, let us briefly outline the major premises of each theory. The first one, the demographic transition theory, describes changes in fertility and mortality over time – from high mortality and high fertility to low mortality and low fertility. This theory was summarized by S. Greenhalgh [Greenhalgh, 1994]. Classical transition theory views social change as unidirectional and progressive, assuming that societies move irreversibly toward greater homogeneity. Greenhalgh [1994:10] summarizes the main premises of demographic transition theory as follows:

1. Fertility transition is a phased process. Societies begin at the primitive or traditional stage and end at the advanced or modern stage.

The concept of demographic transition has four stages, including preindustrial, transition, industrial, and postindustrial stages. The preindustrial stage is characterized by a stable population, with high death rates, due to low standard of living, and high birth rates due to the need to compensate for deaths. The second stage is the one, during which the population begins to increase due to continued high birth rates and declining death rates as a result of an increase in the standard of living. The industrial stage follows and is characterized by continued population increase, despite the declining birth rates and low death rates, which result from increased standard of living and changes in social views. The final stage is the postindustrial one, which is when the human population stabilizes, due to low birth rates and low death rates.

2. Fertility transition is a homogenizing process that produces tendencies toward convergence among societies.

Most of demographic transition theory proponents claim that in the longrun all countries that undergo the transition will have the similar fertility rates, with Total Fertility Rate approximating 2.12.2, or falling below it.

3. Fertility transition is a process of Europeanization (or Americanization).

Demographic transition is an inductive theory that originated from empirical analyses of how Western populations have changed over time. Unlike many other population theories, the demographic transition theory is based on the actual experiences of European countries and the United States. In fact, this theory generalizes the historical sequence and pattern of changes in vital rates that were typical for Europe and, to some extent, the US.

4. Fertility transition is an irreversible process. Once started, it cannot be stopped.

This claim implies there is no way fertility rates will ever return to the pretransitional level, though proponents of the theory do not rule out certain fluctuations in the fertility rates (including slight increase) after the completion of the demographic transition.

5. Fertility transition is a progressive process; in the long run, it is desirable.

Progressive tendencies are observed in the mutual adjustment of reproductive functions and women’s selfactualization, as well as in the increased potential for investing more time and financial resources in the upbringing, health, and education of children.

6. Fertility transition is a lengthy process.

When applied to demographic developments in Europe, the process spans up to two centuries. In contrast, in some modern societies (e.g., the four “economic tigers” of Southeast Asia – South Korea, Hong Kong, Taiwan, and Singapore) – the demographic transition lasted only a few decades. The pioneers and, later, the followers of demographic transition theory – W. Thomson [2002], K. Davis [1986], D. Kirk [1996], and F. Notestein [1945] – initially sought to explain the changes in the European demographic situation from the early 19th to the early 20th century. They view the demographic transition through the lens of social change parameters such as progress, industrial development, the emergence of a “technological civilization,” and other characteristics of the modernization process. All pioneers of this approach adhere to the idea of a threestage transition process, as outlined by the founder of this school, A. Landry [Landry, 1982].

Later, K. Sax [Sax, 1956] expanded the demographic transition model by adding a fourth stage. This stage is often referred to as the posttransition phase, though it is considered part of the overall demographic transition model. Another name for this stage is the stationary population phase. At this point, birth and death rates are both at low levels and once again approach equilibrium, similar to the beginning of the transition. However, the birth rate may even fall below the death rate, leading to an overall population decline. The total fertility rate fluctuates around two children per woman, and population growth is either zero or even negative.

The institutional theory of fertility essentially emerged as a response to the shortcomings and the “universalism” of the classical transition theory. It emphasizes the contextual and often situational nature of reproductive decisionmaking. The core principles of institutionalism focus on the uniqueness of each case of demographic development, shaped by institutions that have the most significant impact on birth and death rates. Institutional theory introduced several explanatory claims of its own. First, the theory proponents elaborated on the very concept of institutions, and singled out the ones that are fertility related. Second, it explained demographic change in terms of pathdependency that is closely related to the uniqueness of institutional contexts for any given country or groups of countries. And, third, it came up with the explanation of the mechanism of how institutional settings are perceived by individuals, and how they influence fertility decisionmaking.

Let us begin by clarifying the first point. The institutions that could be used as determinants or predictors of fertility are not, as one of the main proponents of institutional theory, J. McNicoll, put it, “…tangible institutional entities such as prisons or hospitals,” but rather “groups of behavioral rules governing actions and relationships in recurring situations” [McNicoll, 1994: 45]. These rules can be written or unwritten, but it is well known that violations are subject to sanctions, imposed by authorities.

McNicoll also emphasizes the multifaceted character of institutions, which have both material and cultural antecedents. The latter share properties with cultural traits, such as symbols and beliefs. Social institutions impacting fertility plausibly possess this multifaceted nature. Acknowledging that institutions are not neatly classifiable, McNicoll suggests the following enumeration of some supposedly fertilityrelated institutions: (1) family and local community, (2) family and property law and the local dimension of public administration, (3) family and the stratification system, and the mobility paths it accommodates, and (4) family and the labor market [McNicoll, 1994: 11]. Moreover, the scholar highlights the institutional context of the relationship between the state and the individual, as governments attempt to influence fertility through public policy. K. Mason suggests focusing on macrolevel institutional characteristics such as mass education, the legal status of women, and the system of gender stratification. She recommends conducting analyses at an aggregated level [Mason, 1984: 77].

The second, and arguably the most important, explanatory claim of institutional theory employs the concept of pathdependency. This concept implies that emerging institutions, or “clusters of behavioral rules,” are partially dependent on previous choices and developments. These earlier choices stemmed from behavior and were influenced by both historical context and societal expectations. Newly established institutions, in turn, determine future choices, with their array, largely dependent on the types of institutions that were already present at the previous “path.”

The key word in the institutional theory’s pathdependency approach is “uniqueness.” As D. van de Kaa put it: “The institutional endowments of a society will reflect its unique history; hence, the demographic response of societies to changes in economic circumstances, in the probabilities of survival, in security risks of families and individuals, in sex roles, or in the policies pursued by their government, will in some measure be unique” [van de Kaa, 1996: 427]. The theory’s emphasis on the uniqueness of demographic developments due to the specifics of institutions relevant to fertility behavior challenges the universality of demographic transition theory.

The uniqueness of institutional contexts in influencing fertility behavior and outcomes has been demonstrated in numerous empirical studies. For instance, S. Morgan brings “institutional” arguments to explain the relatively high fertility rates in the US (with a TFR approximating 2.1). He cites research, showing how gender and technological changes have impacted important institutions, such as the division of household labor, allowing women’s time spent with children to remain largely unchanged for decades [Morgan, 2003: 595]. Morgan also highlights the significant role of nongovernmental institutions, such as gender equality and flexible work hours, which compensate for the relatively less generous welfare system in the US and contribute to its highest fertility level among developed countries.

In general, the difference between the two theories in explaining demographic dynamics is that demographic transition theory largely emphasizes the universality of demographic change, while institutionalism predominantly stresses the uniqueness of fertility and mortality dynamics in any given country or region. Now, let us turn to the discussion of the debates regarding the appropriateness of these two theories. The main arguments of the opponents are presented below.

Before delving into the dispute on the validity of these two perspectives between A. Vishnevsky and M. Klupt, it is worth making several points relevant to this discussion. First, when assessing any social theory, it is important to treat it as a theoretical model. This implies that, for the most part (if not always), real empirical phenomena do not fully correspond to the theory. T. Burch [Burch, 2018] makes a corresponding point by introducing the concept that theoretical models never fully capture the diversity of related empirical data. Instead, they serve as general, simplified tools designed to approximate existing empirical data. He writes:

“A model is any abstract representation of some portion of the real world. A model may contain basic principles generally regarded as ‘laws.’ In this case, the laws “function as true statements, but not as statements about the world. They are then truths only of an abstract model. In this context, such statements are true in the way that explicit definitions are true” (Giere, 1999, p. 6). A model contains generalizations, but they are formal generalizations, not empirical ones.

Empirical assessment of theory, therefore, relates not to whether a theoretical model is empirically true or false – strictly speaking, all theories and models are false because they are incomplete and simplified representations of reality – but to “how well the resulting model fits the intended aspects of the real world” (Giere, 1999, p. 6). This view stands opposed to many familiar teachings of logical empiricism, which holds that theory is based on empirical laws and judged true or false solely by its agreement with data. The modelbased view is equally concerned with empirical data, but these are used to judge whether a model fits some portion of the world closely enough for a given purpose, not whether the model is true or false in any absolute sense” [Burch, 2018: 4].

This approach implies the following conclusion: “Many theories in behavioral demography which have been rejected because of empirical exceptions or on the grounds they are too simplistic can be viewed as perfectly good theory, especially if they were to be stated more rigorously” [Burch, 2018: 4]. Burch provides an example of a model that fits this requirement: the stable population model. The empirical data rarely, if ever, perfectly fits the parameters of this model; however, it proves to be very relevant and beneficial in demographic analysis and forecasting. The stable population model serves as a yardstick against which actual empirical data on that population is compared. If the empirical data for a country or region doesn’t perfectly fit the model, but approximates it closely enough in structure, growth, and evolution of human populations, this population reproduction is considered to be stable. When analyzing the merits and downsides of the demographic transition theory, it is important to remember that, if employing this approach, it should not be perfectly supported by the empirical data to be considered a good theoretical model.

Second, both scholars make references to the corresponding demographic theories – demographic transition (Vishnevsky) and, more implicitly, institutionalist theory (Klupt). In fact, they both refer, at least initially, to certain variants of these theories. However, neither of them fully acknowledges this. A minor exception is Klupt’s [2008] brief and general reference to the discrepancies within the demographic transition theory (DTT). This issue involves different approaches to defining the main driving forces behind global demographic changes, particularly within the context of the demographic transition theory.

Proponents of the demographic transition theory assign the role of major driving forces behind demographic changes to the factors, related to modernization. These factors include: urbanization, secularization, other ideational changes, increasing education of the population, changes in the position of women in society (including wage equality), a radical shift in the sectoral structure of the economy (from agricultural to industrial), profound changes in the nature of labor, an unprecedented increase in wellbeing, the rising opportunity cost of raising children, and the requirements of the demographic system for maintaining homeostasis (equilibrium). However, there are disagreements among scholars regarding the most significant factors triggering the demographic transition (more on this in the next section).

Third, it is worth mentioning that the debates on the nature of demographic changes extend beyond the academic realm. Proponents of various theories derive practical implications for the need and utility of conducting proactive population policies from their theories. Klupt [2018] argues that modern proponents of the demographic transition theory, due to their deterministic view of changes in fertility, oppose pronatalist policies and, more broadly, are against proactive approaches in general. The scholar discusses the views of the founders of the demographic transition theory, highlighting their proactive stance in various areas of social life, including demographic developments. In our opinion, modern proponents of the demographic transition theory emphasize the improbability of returning to the high fertility rates of the preindustrial era, regardless of the implementation of pronatalist policies. Nevertheless, the success of population policies in bringing fertility rates closer to the replacement level is evident in several countries. A prominent example is the demographic development in France, where a welldeveloped, familyoriented pronatalist policy, combined with a robust public sector, has led to one of the highest Total Fertility Rates in Europe.

Let us begin by discussing several variants of the demographic transition theory (DTT). One of the main points of contention concerns the universality of its applicability. D. Kirk and other scholars argue that DTT was originally formulated to explain demographic developments within a specific historical and geographical context – namely, Europe from the 18th to the 20th century – rather than as a universal theory with predictive power [Kirk, 1996]. However, as B. de Bruijn observes, later scholars have extended the principles of historical demographic transitions to contemporary contexts, implying that any country or nation can follow the evolutionary path of modernization, leading to declines in mortality and fertility rates [de Bruijn, 2006: 552]. This perspective assumes that a significant decline in mortality always precedes a fertility decline, and that lower mortality inevitably leads to lower fertility. Over time, this interpretation has led to DTT being regarded as a universal framework with predictive power. It is in this sense that the fundamental principles of the Demographic Transition Theory are defined and described at the beginning of this section.

A. Vishnevsky [1985] further developed what could be called the “functionalist variant” of the theory. He emphasized the functionalist perspective introduced by T. Parsons in his classical works [Parsons, 1937, 1951]. In these works, Parsons proposed and developed the AGIL framework, which asserts that all social systems require four functional prerequisites: Adaptation, Goal Attainment, Integration, and Latency (AGIL). These requisites are responsible for maintaining equilibrium (homeostasis) within social systems.

Since the demographic system is one such social system, according to Parsons’ approach, whenever there is a threat to this system’s equilibrium, an adaptation mechanism is triggered to restore it – either to its previous state of equilibrium, or to a newly established one.

In the context of the demographic system, its main components (elements, subsystems) are fertility and mortality. Migration plays a role at the regional, national, or settlement level, but on a planetary scale, migration flows cancel each other out. When applying this logic to the demographic transition, the decline in fertility is viewed by the functionalist variant of this theory as the demographic system’s response to the threat to its equilibrium posed by decreasing mortality (i.e., the threat of overpopulation).

The questions that arise regarding this approach are similar to those posed in Parsons’ work. Some of these include: At what stage does the demographic system “sense” the threat to its equilibrium – at the onset of mortality decline, or only when overpopulation becomes a tangible and visible issue? Does the adaptation mechanism operate at the level of a specific country or region, or does it also address global equilibrium? For example, if fertility declines in France in response to a drop in mortality, does this mean to restore equilibrium within France alone, or does it take into account demographic equilibrium across Europe, or even globally, considering developments in other countries?

Vishnevsky argues that the demographic system seeks global equilibrium, attributing regional discrepancies to the time lag required for adjustment and overall homeostasis. However, this concept is difficult to verify empirically. A good illustration of this issue is the interpretation of fertility trends among Native Americans in the U.S. This group exhibits the highest fertility rates among all racial groups. Proponents of the functionalist approach argue that this high fertility rate represents an effort to achieve equilibrium, given the shrinking an already a small number of Native American population. Conversely, opponents attribute this trend to exclusive economic benefits, such as casino ownership, allocated to this racial group.

However, the functionalist variant of the demographic transition theory is not the only explanatory framework. The nonfunctionalist version operates at both macro and micro levels, incorporating a range of factors influencing the transition. These include women’s participation in the labor force, ideational changes (such as shifts in religiosity and secularization), and various aspects of modernization, including improvements in sanitation and urbanization.

According to K. Davis [Davis, 1986: 60], normative control plays a significant role in reducing fertility in this new type of environment. Similarly, F. Notestein emphasizes the importance of norms in lowering fertility during the third stage of demographic transition. He cites factors, such as “growing individualism” and a desire to break with “old taboos,” arguing that “the reduction of fertility requires a shift in social goals from those directed toward the survival of the group to those directed toward the welfare and development of the individual” [Notestein, 1945, pp. 3757].

To summarize, these interpretations of demographic transition highlight macrolevel changes in demographic processes associated with modernization, such as urbanization, industrial growth, improved sanitation, and, notably, increased female labor participation. Unlike the functionalist variant of demographic transition theory (DTT), which focuses on maintaining equilibrium within the demographic system, these perspectives do not assume such an equilibrium. Instead, they represent what could be classified as the nonfunctionalist version of the theory.

An example of a nonfunctionalist approach to demographic transition, which focuses on microlevel fertility decisionmaking without reference to macrolevel demographic system requirements, is presented by D. van de Kaa [van de Kaa, 1996: 407]. The author outlines four hypotheses regarding how fertility responds to a decline in infant mortality:

1. Child Survival Hypothesis
2. Child Replacement Hypothesis
3. Reduction in Uncertainty Hypothesis
4. Insurance Against Widowhood Hypothesis

As van de Kaa notes, the first two hypotheses pertain to the experiences of individual couples, while the latter two operate at the community level.

Now, let us turn to the divisions within institutional theories of fertility. As mentioned above, the pathdependencybased institutional approach emphasizes the uniqueness of demographic development in each continent, region, or country, contrasting with the universalistic assumptions of demographic transition theory. However, an increasing number of studies within the institutional theory framework adopt a somewhat different approach. This perspective considers not only the unique institutional influences on fertility within individual countries, but also the commonalities in institutional settings across various nations.

One example is the work of R. Rindfuss [Rindfuss et al., 2003], which identifies patterns of institutional settings across different groups of countries, and examines their corresponding demographic responses. As the authors note, they “…look at the interplay between the uniqueness of countries (or individuals) and their response to similar forces and constraints” [Rindfuss et al., 2003, p. 413].

Another notable example of a distinct branch within institutional theory is the work of McNicoll [McNicoll, 2006]. This study focuses on seven East Asian countries: Taiwan and South Korea (the “tiger” economies), Thailand, Malaysia, and Indonesia (the “second wave” countries), and China and Vietnam (the “marketLeninist” economies). The author examines commonalities in both demographic and economic developments, highlighting the significant role of government programs in fertility transition. Specifically, he discusses successful antinatalist policies as key lessons from the East Asian experience.

At the same time, McNicoll highlights the unique aspects of demographic transitions in each of these countries, which are largely shaped by the differences in their economic structures, the state’s role in managing fertility decline, and their initial institutional endowments and characteristics.

Perhaps, an even more pronounced example of this institutional approach is McNicoll’s typology of demographic transitions across various regions [McNicoll, 1994]. He identifies five archetypes of institutional endowment, broadly associated with different geographic regions: “traditional capitalist,” “soft state,” “radical devolution,” “growth with equity,” and “lineage dominance.” According to this typology, McNicoll argues that the “radical devolution” archetype (e.g., China) and the “growth with equity” archetype (e.g., East Asia) have been associated with the most rapid fertility transitions. Conversely, societies characterized by “lineage dominance” (e.g., subSaharan Africa) have experienced the slowest fertility decline.

The strengths and weaknesses of demographic transition theory have become evident through historical and contemporary empirical testing. While the general trend of mortality and fertility decline during modernization has been confirmed, studies, such as the Princeton Project, have struggled to identify a definitive socioeconomic indicator that consistently explains the onset of fertility decline in Europe [Watkins, 1986, p. 484].

De Bruijn argues that “socioeconomic factors, which were emphasized by transition theory, appeared to be either spurious or inconsistent in explaining the timing or tempo of the decline” [de Bruijn, 2006, pp. 552–553]. He cites the example of simultaneous fertility declines in England, the most economically advanced nation at the time, and Hungary, which lagged significantly behind. Another illustrative case is China, Kerala, and Sri Lanka, where fertility rates hover around the level of simple population reproduction, despite not meeting the socioeconomic conditions, traditionally required for fertility decline.

Moreover, de Bruijn challenges the transition theory’s assumption that mortality decline always precedes fertility decline. Similarly, E. van de Walle [van de Walle, 1978, p. 390] provides an example of France as a case, where fertility decline occurred before a significant drop in mortality – contradicting the sequential pattern, proposed by transition theory. This example is not unique, further questioning the universality of the theory’s core premise.

Research by J. Knodel and E. van de Walle [Knodel & van de Walle, 1979] demonstrated that there is no consistent association between the level of socioeconomic development and the timing of fertility declines across many European countries. Additionally, no significant link was found between the timing of mortality and fertility declines in most countries. In fact, in some cases, such as the ones in England and Belgium, fertility decline often preceded the decline in infant mortality.

As previously mentioned, the demographic transition theory – particularly its functionalist variant – considers mortality decline to be a prerequisite for fertility decline. The analysis of this assumption has largely shifted toward examining the relationship between child mortality and fertility declines. However, as the examples above illustrate, many of the weaknesses of demographic transition theory, revealed by detailed empirical research, are tied to this functionalist interpretation. This variant, as mentioned above, assumes that fertility decline follows mortality reduction as a mechanism for restoring equilibrium within the demographic system.

The reversal of mortality and fertility declines sequences in several countries challenges Vishnevsky’s metaphorical comparison of demographic transition stages to a “spring always following winter,” which implies an inevitable progression. Instead, demographic transitions in various countries might be better compared to situations, where winter sometimes follows spring, or where both seasons occur simultaneously – an analogy that, of course, defies natural patterns.

Several cases further challenge the assumptions of demographic transition theory, particularly the lack of a direct association between socioeconomic development and demographic changes, as highlighted by de Bruijn [2006, pp. 552–553]. M. Klupt’s criticism rightly targets the theory’s claim to universality and its failure to predict variations in the rates and patterns of mortality and fertility change across different countries and regions – despite the fact that these variations still fall within the general reproductive regimes, predicted by the theory. In contrast, the examples, provided by de Bruijn and other scholars, question the theory’s core premise by challenging the direct relationship between socioeconomic development and demographic change.

An even stronger challenge to the demographic transition theory comes from cases, where no relationship exists between socioeconomic development and the onset of both mortality and fertility declines. Such findings undermine all variants of DTT, as modernization is considered to be the primary driver of demographic transition – a foundational principle of the theory.

It is crucial to distinguish between a theoretical model that is overly general – applicable only within specific contexts – and one that is fundamentally flawed. The former suggests the need for refinement or restatement, while the latter implies that the theory may be inherently incorrect, and should be reconsidered or discarded.

Now, let us examine M. Klupt’s arguments against the validity of the demographic transition theory. One of his primary critiques differs in nature from those previously discussed. Klupt analyzes the dynamics of mortality and fertility across different countries, and highlights the vast discrepancies in the rates of change in both processes by the end of the transition period and beyond. One line of criticism from A. Vishnevsky regarding the examples, provided by M. Klupt to illustrate these variations, is that they are difficult to verify. It would be more accurate to say that Klupt’s institutional explanations for variations in demographic processes across different countries are still a subject of debate, despite being wellfounded (which is typical for the interpretation of most social phenomena).

An example of such differing interpretations concerns Italy’s notably low fertility rates. Klupt attributes this trend to various institutional factors, including familism, the high cost of renting or purchasing housing, and, paradoxically, the influence of the Catholic Church. He argues that the Church discourages young couples from entering “cohabitation marriages” (unmarried partnerships). Combined with high housing costs and strong familistic values, this leads to delayed marriages and, consequently, lower completed fertility rates.

This explanation has been debated among scholars [Eaton et al., 2004]. While acknowledging the Church’s influence on fertilityrelated norms, they argue that its impact on certain family issues has diminished, particularly among younger generations. They note that although Italy is one of Europe’s most religious countries – where 98% of Italians identify as Catholic – only 30.4% consider religion very important, and just 25.4% of Italians aged 18–49 attend mass weekly, with even lower figures in urban areas [Eaton et al., 2004: 3]. Furthermore, like other European countries, Italy has experienced increasing secularization over several decades. This, scholars argue, has influenced attitudes toward contraception and abortion, leading to a “sharp increase in both the acceptability and use of contraception and abortion methods” [Eaton et al., 2004: 3], despite the Church’s firm opposition.

While religious norms may no longer resonate with Italians on certain familyrelated issues, they could still influence others. However, this is not necessarily the case. The lower proportion of young Italian couples living in consensual unions, compared to those in Northern Europe, is statistically welldocumented, and its negative impact on fertility rates is quite clear. Yet, whether religious institutions play a dominant, minor, or negligible role in this trend remains uncertain. Therefore, the claim that Italy’s low fertility rate is directly linked to Church doctrine on cohabitation requires further empirical justification.

The vast differences in demographic developments across countries and regions, as highlighted by M. Klupt, are of great significance, despite varying interpretations. This importance is further reinforced by the tendency to interpret theoretical models – such as the demographic transition – too literally, overlooking the fact that they are simplifications of a far more complex and diverse reality. Klupt’s work provides valuable insights into the diversity of demographic developments; however, most of his examples do not fundamentally refute the core assumptions of demographic transition theory. Across most countries, the variations in transition patterns, empirically demonstrated by Klupt, have not altered the remarkably similar end result: a decline in both mortality and fertility – typically, to a low or extremely low levels. This outcome aligns with the key assertions of all versions of the demographic transition theory. Perhaps, most important, as A. Vishnevsky notes, is the shift toward a new type of demographic behavior.

As with any theoretical model, exceptions exist within the demographic transition framework that warrant further analysis. The first, rightly noted by Klupt, involves cases of stalled fertility decline – a widely discussed phenomenon that will be examined in subsequent studies. The second exception, also noted by Klupt [2008], pertains to the persistently high fertility rates in small towns within the Bible Belt and the Midwest, particularly among the U.S. farming population, predominantly evangelicals. The presence of a highfertility segment within one of the world’s most technologically advanced nations challenges the demographic transition theory. If this trend persists and/or the proportion of this demographic does not decrease, it could pose an even greater challenge to the theory. It remains premature to draw definitive conclusions, but early indications suggest that this phenomenon is on decline.

Preliminary evidence from recent General Social Survey (GSS) data in the U.S. supports this trend. Scholars, examining contemporary fertility patterns among evangelicals and nonreligious respondents (“nones”) observe the following:

“In the early 1970s, evangelical households averaged just over 2.5 children, slightly higher than the national average of 2.3 children. At that time, nones had a notably lower fertility rate, with an average of 1.4 children. More recent data shows a decline in fertility across both groups. By 2021, the average number of children reported by respondents had decreased to 1.8, reflecting a dip of 0.5 children over the past five decades.

For evangelicals, while there was a noticeable decline in fertility rates between 1972 and 2000, recent figures show a slight rebound. Currently, the average evangelical family has about 2.1 children, which is just above the national average. In contrast, nones have experienced a smaller decline in fertility rates, with the average number of children reported at 1.3. This represents a slight increase from two decades ago but remains significantly below (50%) the national average” (Burge 2022).

Data from the GSS and other statistical sources are frequently cited in both professional demographic studies and Christian literature to support this observed trend. A particularly telling headline from a recent religious journal reads: “Americans Are Having Fewer Children. Evangelicals Are No Exception” [Huska, 2020].

However, this conclusion requires further verification – not only to confirm the persistence of the trend, but also to account for demographic nuances within the evangelical population. Klupt appears to refer specifically to a subset of evangelicals – those residing in small towns and rural areas in the Deep South and Midwest. It remains possible that fertility decline within this particular group is either not occurring, or is less pronounced than in the broader evangelical demographic.

Klupt also references several studies [EspingAndersen & Billari, 2015; Goldscheider et al., 2015; Anderson & Kohler, 2015; Myrskylä et al., 2009] that explore the concepts of the “gender revolution” and the “gender equality dividend.” These frameworks attempt to explain emerging fertility patterns in developed countries, particularly the reversal of the traditionally negative correlation between socioeconomic development and fertility rates. Most of these studies focus on the posttransition stage of demographic development, prompting Klupt [2018] to question, whether these modern concepts should be considered extensions of demographic transition theory.

According to Klupt, these new trends challenge the core assumptions and forecasts of demographic transition theory. He writes:

“Not only is the diagnosis different, but so is the prognosis. Vishnevsky believes that in most postindustrial countries, ‘the ultimate fertility rate of real generations is declining, with no serious alternatives in sight’ [Vishnevsky, 2012, p. 84]. The authors of the aforementioned studies are more optimistic and, albeit with many reservations, suggest that as gender equality continues to expand, fertility rates will increase [Anderson & Kohler, 2015, p. 398; EspingAndersen & Billari, 2015, p. 9]” [Klupt, 2018, p. 11].

In fact, M. Myrskylä and his coauthors [Myrskylä et al., 2009] concluded that the inverse relationship between fertility and development level not only lost its universal character, but also reversed into a direct relationship in the most developed countries. They observe that among the 25 nations with the highest Human Development Index (HDI) – a composite measure of health, wealth, and education – only one currently maintains a total fertility rate above the replacement level [Myrskylä et al., 2009, p. 8]. Nonetheless, due to this emerging trend, they predict a slowdown in the decline of fertility, which, when combined with migration flows, could eventually stabilize or even reverse population de cline in these countries.

The conclusions, related to the inverse relationship between the Human Development Index (HDI) and fertility, are very important for assessing the demographic future of developed countries. However, the researchers do not believe that the changing nature of the relationship between HDI and fertility will alter the prediction of proponents of the demo graphic transition theory regarding negative natural population growth (primarily driven by fertility rates below the replacement level) at the fourth, posttransition stage. They assert: “As long as the most developed countries remain focused on improving their citizens’ wellbeing and have adequate institutions, growth and development will likely reverse the fertility decline – even if we cannot expect fertility to rise above replacement level again. Consequently, we expect that highly developed countries will experience relatively stable population numbers or even population growth in cases where immigration is significant. For countries where immigration plays a secondary role in demographic change, our analysis suggests a slower population decline than currently projected in official demographic forecasts” [Myrskylä et al., 2009, pp. 78].

Yes, fertility may increase, but not even to the level of simple replacement! And, even with immigration – if it remains moderate, rather than substantial – the population will continue to decline, albeit at a slower pace. Does this seem like a radical deviation from the overall demographic transition theory’s forecast for the fourth, posttransition stage?

It is also important to note that demographic developments in the fourth stage largely align with the predictions of demographic transition theory. Specifically, the theory’s assumption about the inverse relationship between women’s labor force participation and fertility rates should not be subject to contention. This relationship was proposed to be applicable only to the period of the demographic transition, not to the posttransitional stage. It is quite understandable that in today’s new reality, this inverse relationship does not necessarily persist, given the differences between women’s labor force participation during the demographic transition and today – where remote work, flexible schedules, and “a little help” from increasing gender equality play a role. However, the emergence of new patterns under new “contingent conditions” does not mean that previously established patterns under older conditions were incorrect.

To illustrate, Lobachevsky’s discovery of parallel lines intersecting in threedimensional space does not disprove Pythagoras’s theorem concerning parallel lines in twodimensional space. Each set of findings pertains to different contexts and dimensions. Lobachevsky’s assertion that two parallel lines can intersect in threedimensional space does not disprove the Pythagorean theorem, which holds in another set of “contingent conditions” – namely, twodimensional space.

A slightly different approach is taken by other scholars, T. Anderson and H.P. Kohler [Anderson, Kohler, 2015], who are also cited by Klupt. While acknowledging exceptions and deviations in new research findings on the relationship between socioeconomic development, gender equality, and low fertility, these scholars seek to overcome the limitations of previous studies, which are constrained by their shortterm focus (typically, beginning from the late 20th century).

Anderson and Kohler propose a longterm perspective on this issue, covering a broader historical timeframe starting from the early 20th century. Their aim is to provide a new theoretical understanding of the relationship between low fertility, socioeconomic development, and gender equality. They argue that the onset and longterm pace of socioeconomic development are inherently linked to a key factor influencing fertility fluctuations in developed countries – namely, different regimes of gender equality. Specifically, they assert that these regimes are closely connected to fertility changes through a mechanism of demographic feedback, referred to as the “gender equality dividend” [Anderson, Kohler, 2015: 381]. This concept explains, how improvements in gender equality can, over time, lead to shifts in fertility rates.

Scholars distinguish between firstwave modernization countries, where socioeconomic development progressed more gradually throughout most of the late 19th and 20th centuries, and secondwave countries, where modernization began in the second half of the 20th century, and was often characterized by significantly faster economic growth than in firstwave countries.

This distinction leads to differences between the two groups in terms of gender equality dynamics and levels, which, in turn, result in variations in fertility rates. According to the scholars, “these differences have farreaching implications for current and future fertility trends and family dynamics, helping to explain why fertility has stabilized at a moderately belowreplacement level in some countries, while in others, it has declined to very low or ultralow levels” [Anderson, Kohler, 2015: 382].

Thus, the key difference between these two groups of countries lies in fertility rates: in one case, fertility remains slightly below the replacement level, while in the other, it falls to a very low or ultralow levels (i.e., significantly below replacement). This pattern aligns perfectly with the general predictions of the demographic transition theory for the posttransitional stage. Moreover, the scholars cited do not anticipate major changes in future demographic developments.

According to Anderson and Kohler [2015], demographic changes in certain countries will lead to similar outcomes, even considering the noted shift in the relationship between fertility and the Human Development Index (HDI). They write: “Our theoretical framework cautiously suggests that ‘thirdwave’ countries – including China, Brazil, and India – may replace secondwave countries as the new frontier of low and ultralow fertility in the 21st century” [Anderson, Kohler, 2015: 398].

This indicates that future fertility dynamics are unlikely to exceed the replacement threshold. Moreover, any modest fertility increase could be temporary, as it may be offset by counteracting trends, partly driven by labor market instability. For instance, in the Nordic countries – Finland, Sweden, Norway, Denmark, and Iceland – there has recently been a sharp decline in fertility. This trend contradicts the traditionally assumed positive relationship between a welldeveloped welfare system and fertility rates. The trend is remarkably similar across all Nordic countries, both in terms of period and cohort fertility, leading scholars to describe it as the “Nordic fertility regime.”

All of this allows us to answer M. Klupt’s rhetorical question about the newly discovered connections between women’s participation in the workforce and fertility: “Are these modern concepts a continuation of the theory of demographic transition?” as follows: Yes, these concepts are organic continuations and additions, as they summarize the current changes in important links, related to fertility, and make appropriate adjustments to the explanations of new shifts in the demographic process, within the framework of the correctly predicted overall trend of the theory of demographic transition.

In conclusion to this part of the discussion, it is important to support A. Vishnevsky’s assertion that the theory of demographic transition does not imply the denial of any changes in the posttransition phase, and that further research is needed to address the unresolved issues of the theory of “demographic revolution” (Vishnevsky 2017). Of course, this holds true as long as these differences do not cease to align with the main predictions of the theory for this phase – inevitable declines in fertility and mortality (with fertility remaining below the replacement level) and modernization as the cause and trigger of these changes. The theory of demographic transition is, of course, not the “end of history” in the spirit of Fukuyama. M. Klupt’s ideas about the need to investigate these variations are relevant and valid (their analysis is provided below).

What are the most promising response strategies to new realities, that allow for a more adequate explanation of both past and current trends in fertility and mortality? Do the limitations and universality of the original assumptions of the demographic transition theory (DTT) necessitate abandoning the theory altogether, or, rather, do they call for its restatement? Consider some attempts to reformulate to answer these questions.

Such an attempt was made in the study by Podrażka (1989). In this work, European countries were classified based on the duration of their demographic transition into the following categories: 70–80, 80–90, 90–100, and more than 100 years. The transition duration was described as very short, short, mediumlength, and very long, respectively. The emergence (peak) and intensity of the demographic explosion were classified based on the natural increase rate per 1,000 people: 12, 12–14, 14–16, and more than 16. The demographic explosion itself was characterized as very weak, weak, medium, or strong. Based on these criteria, seven types of demographic transition were identified.

Another approach – using cohort analysis to restate the demographic transition theory (DTT) – was proposed by T. Frejka (2016). The author used a slightly different term, referring to this process as a “revision of the demographic transition.”

Based on cohort analysis, Frejka identified four distinct types of transition:

1. Western transition – characterized by large fluctuations in the cohort total fertility rate (CTFR).
2. Central and Eastern European transition – defined by a stable CTFR range, approximately two births per woman in birth cohorts from the 1920s to the 1950s.
3. Southern European transition – marked by a relatively steady decline in CTFR over the course of a century.
4. East and Southeast Asian transition – characterized by a rapid decline in CTFR, starting in the mid20th century.

While Frejka acknowledges the general accuracy of Notestein’s predictions regarding the demographic transition, he disagrees with Anderson and Kohler’s perspective on the univer sal increase in fertility due to gender equality. Whereas the cited scholars argue that fertility decline is a universal component of the fertility transition in early 20thcentury cohort CTFRs across all countries, Frejka maintains that this phenomenon occurred only in countries following the “Western” transition model.

Equally important is Frejka’s assertion that while mortality will continue to decline, and the future of fertility remains uncertain, a balance between low mortality and low fertility has not yet been achieved. This statement further underscores the importance of distinguishing between different versions of the demographic transition theory (DTT). If the nonfunctionalist version of the theory, as formulated by Notestein, is largely confirmed (at least for nonEuropean regions), and only requires some modifications, the functionalist version – which claims that achieving equilibrium in the demographic system is an inherent characteristic – is challenged by Frejka.

Another reformulation of DTT was proposed by K. Mason [Mason, 1997]. She suggested three time periods for evaluating the theory: millennial, centennial, and decadal. The scholar asserts that the premises of DTT are plausible on a millennial scale, but often contradictory on a decadal scale: both in Europe and in developing countries, “the correlation between the level of urbanization or industrialization and the decade in which countries or provinces first experience a decline in fertility is weak” [Mason, 1997: 444]. On a centennial scale, the premises of DTT remain valid, but require certain clarifications.

Mason writes: “However, the demographic history of individual countries aligns less well with the theory. For example, several Asian countries (including Bangladesh: [Amin et al., 1995]) and Latin American countries (such as Haiti: [Zavala de Cosio, 1996]), which are currently experiencing a fertility transition, are agrarian and underdeveloped; this clearly contradicts the idea that development and modernization lead to a decline in fertility. Thus, the demographic transition theory contains ideas that are difficult to ignore and that continue to persist despite the barrage of criticism directed at it. However, in its original form, the theory is incomplete” [Mason, 1997: 444].

No less important is that Mason provides three explanations for why the assumption of a single cause for the demographic transition is incorrect. These include: the existence of potentially significant influences on fertility only at certain times or in specific places; evidence of the diffusion of information and ideas about fertility limitation, which affects reproductive behavior even in the absence of major structural changes; differences in pretransition reproductive regimes.

This represents a radical deviation from the original narrative of the demographic transition theory (DTT), which identifies socioeconomic modernization as the sole cause of the onset of the demographic transition. Nevertheless, it remains a variant of DTT, as economic modernization is still considered either the primary driving force, or one of several forces (along with institutions) in many contexts.

Finally, there is another, more substantial reformulation of the demographic transition theory – the variant, proposed by J. Caldwell [Caldwell, 1976, 1977, 1981]. Due to its significant deviation from the original concept of DTT, it has been given its own name: the net wealth flows theory. For some unknown reason, this theory is not mentioned in the debate between the two scholars. Klupt [2008] briefly refers to this theory, describing its main premise – the reversal of the direction of wealth flows – however, the theory’s claims related to the incomplete explanations of DTT are not addressed. Nevertheless, the wealth flows theory is capable of explaining certain demographic phenomena that do not fully align with the assumptions of the classical DTT narrative.

This key aspect of Caldwell’s theory is its emphasis on the emergence (nucleation) of the family. The role of family emergence in altering the direction of wealth flow is, in fact, a crucial component of Caldwell’s reformulation of the demographic transition theory. He proposes the possibility of emotional nucleation preceding economic nucleation. Caldwell’s main premise is that the family revolution does not necessarily coincide with economic modernization.

Accordingly, Caldwell argues that in some countries, economic modernization is not necessarily accompanied by certain types of social changes (including family nucleation). This explains why some countries maintain persistently high fertility rates despite high levels of urbanization and a significant nonagricultural economic sector. The reverse is also true: a family revolution may precede economic modernization.

In this case, a corresponding shift in the direction of intergenerational wealth flows leads to a decline in fertility, independent of economic progress. This explains demographic phenomena that the demographic transition theory (DTT) failed to interpret – such as the sharp decline in fertility in predominantly agrarian Bulgaria between the First and Second World Wars, or the sustained fertility levels in urban Egypt and most countries in East and Southeast Asia during the 1950s.

Caldwell’s theory also distinguishes between modernization and Westernization. The latter includes cultural factors (e.g., attitudes toward consensual unions, cinema, and music) that may precede economic modernization. This approach could, at least partially, explain demographic trends in India before the onset of modernization. About 30 years ago, the country did not yet exhibit its current rapid GDP growth, the rise of hightech billionaires, or the expansion of a highly educated IT sector. However, Bollywood was booming, and the Internet facilitated access to Western films. This contributed to the spread of new family and fertility patterns, including cohabitation outside of marriage and family planning. In this sense, Westernization occurred – albeit without an economic modernization.

Klupt himself advocates for employing the concept of “multiple modernities” as an alternative approach to studying demographic changes. He writes:

“... the concept of multiple modernities, whose development is associated with the names of S. Eisenstadt, B. Wittrock, and N. Müzelis, is gaining increasing popularity, while linear and ‘Westcentric’ concepts – such as the end of history or democratic transit – are taking a back seat” [Klupt, 2010: 60].

In our view, this marks a departure from Klupt’s earlier works, where he defended an individual approach to studying each country, in the spirit of the first version of institutional theory (the “casebycase approach”). In that earlier framework, Klupt emphasized the uniqueness of social and demographic trends in each geographical region, and assigned a central – if not exclusive – role to the specific institutions of each country in shaping new demographic patterns.

On the contrary, “multiple modernities” align more closely with the second version of institutional theory, which involves the application of typologies and clusters. This is not merely a semantic distinction. The “multiple modernities” approach suggests the presence of common features in demographic development – not only within each cluster (type of modernity), but also across different clusters.

After all, the existence of any form of modernity implies that modernization is either largely completed, or actively underway. Paraphrasing the wellknown phrase about the major cause for electoral preferences in the United States – ”It’s the economy, stupid” – one might say: “It’s still modernity, stupid”.

Yes, modernity takes different forms, with unique features and variations, but it remains a crucial force in driving demographic transitions. This perspective, along with the ones discussed above, can be considered a reformulation of the demographic transition theory (DTT).

This brings us to the possibility of integrating compatible elements from various demographic theories. It is difficult to agree with Vishnevsky [2015], who argued that attempts to combine different theoretical approaches inevitably lead to distorted formations. The development of Sociology – from which demographic theories have borrowed many concepts and methodologies – has followed the opposite trajectory. Sociology has always been, and remains, multiparadigmatic.

Klupt [2014] also supports the idea of multiparadigmatic approaches in Demography, particularly in relation to theories. Ultimately, J. Alexander [Alexander, 1982] introduced the idea and strategy of integrating valid components from major sociological theories – including functionalism, conflict theory, interactionism, and exchange theory.

A similar approach to integrating compatible elements of major demographic theories was proposed in a recently published article [Frantsuz, 2024]. However, given the diversity of these theories, it is essential to identify, which versions can be combined and which cannot. For example, it would be impossible to merge the first version of institutional theory – which assumes the uniqueness of each case – with the demographic transition theory and its reformulations, all of which presuppose some level of commonality (similarity).

In reality, institutions and modernization are not entirely separate entities; rather, they reinforce each other. A key example is the role of the state as an institution in the demographic transition. As noted by S. KirdinaChandler [2019], there are significant differences in the state’s role between Western and nonWestern societies. Klupt [2008] advocates for an institutional approach in studying demographic development, arguing that it is “one of many possible methodologies, based on principles, alternative to demographic transition theories.” If the scholar refers to an alternative to the deterministic and overly general assumptions of the original demographic transition theory (DTT), he is correct. However, many refor mulations of DTT have already addressed these shortcomings. Most of the scholars who have proposed these reformulations, see institutional perspectives not as an alternative, but rather as a complement to demographic transition theory.

That said, Klupt [2008] rightly acknowledges that DTT traditionally incorporates only certain institutions into its analysis. He proposes expanding the theory by incorporating various institutional components in order to better explain demographic changes. Many of these proposals appear highly relevant and useful, particularly the idea of considering “institutional traps.”

Additionally, some scholars support the definition of scope conditions – delineating scopes where DTT applies, and the ones where it does not. For example, W. Lutz [2006] – while generally recognizing the strong predictive power of DTT – writes: “…the demographic transition paradigm, which has been very useful in explaining global demographic trends throughout the 20th century and still possesses significant predictive power in forecasting future trends in highfertility countries, says nothing about the future of fertility in Europe” [Lutz, 2006: 25]

Some scholars explicitly or implicitly support the incorporation of institutional characteristics to explain demographic transitions across different countries. Emphasizing the common global patterns of the demographic transition, F. Willekens identifies an institutional factor – ”path dependence” – as a key element in explaining variations in this process. He writes: “For example, the dominant method of birth control in the early stages of the fertility transition may remain dominant for a long time. Examples include abortion in Russia, sterilization in India, and condoms in Japan. The adoption of these dominant methods in these countries is linked to specific conditions, key actors, or policies at the earliest stages of the transition, as well as to positive feedback mechanisms that reinforce practices, established early on (Arthur, 1989). During the evolution of the process, institutions (including rules and organizations) may emerge or be created to facilitate, constrain, or regulate the process” [Willekens, 2014: 7]

A similar conclusion is drawn by J. Casterline, who highlights the impact of path dependence on the rate of fertility decline, stating: “Path dependence can lead to changes occurring either faster or slower than one might expect” [Diffusion processes and fertility transition: Selected perspectives, 1999: 36]. Additionally, in his review of fertility decline theories over the past fifty years, D. van de Kaa asserts: “Overall, sufficient material has been accumulated to conclude that path dependence and institutional aspects are largely responsible for the regional characteristics that may emerge in the process of demographic transition” [van de Kaa, 1996: 428].

These examples and approaches demonstrate just a fraction of the promising strategies for integrating compatible components of demographic theories. Such integrations represent a valuable direction for both future academic discussions and the study of demographic trends.

The discussion between the two scholars is likely the first comprehensive analysis of existing demographic theories explaining longterm global demographic changes. It highlighted key issues and proved to be highly stimulating. We hope that this dialogue will continue as new demographic phenomena and fresh theoretical concepts emerge, albeit without the participation of A. Vishnevsky. However, it is important to acknowledge certain limitations in the analysis of this discussion, which should be considered in future debates and research.

First, it is crucial to establish clear epistemological criteria for evaluating the validity of demographic theories. Should we adopt a logical empiricist approach, where a theory is judged true or false based solely on its alignment with empirical data? Or should we instead follow a modelbased approach, where a theory is considered valid as long as it sufficiently corresponds to a particular aspect of reality?

Second, demographic theories should be evaluated not only as unified wholes but also in terms of their variations. Given the significant differences between various versions of many theories, this approach would allow for a more precise and nuanced assessment of their claims.

Third, discussions should not be confined to a select set of theories, but should encompass perspectives from all relevant theories and their restatements.

Fourth, it is crucial to distinguish between demographic changes in developing countries that occurred in past centuries and those unfolding today. Among other factors, globalization plays a pivotal role in shaping contemporary demographic trends in these regions. Additionally, it is necessary to differentiate between: theories that are outright false or poorly substantiated; theories that apply only within specific contexts; and, theories that correctly identify general trends but fail to account for regional variations.

Finally, future research and discussions should focus on integrating compatible components from various demographic theories. This synthesized approach would contribute to the development of a more comprehensive and cohesive body of knowledge in the field of demography.

Burge R (2022) ‘Goddenying’ women and selfreplacing Christians: How religion changes birthrates. RNS Religion News Service. URL: https://religionnews.com/2022/09/08/goddenyingwomenandselfreplacingchristianshowreligionchangesbirthrates

Huska L (2020) Americans are having fewer kids. Evangelicals are no exception. Christianity Today, JanuaryFebruary 2020. URL: https://www.christianitytoday.com/2020/01/americansarehavingfewerchildrenevangelicalsarenoexc/

Yuri Aleksandrovich Frantsuz – Candidate of Economics, PhD in Sociology, Research Faculty, University of New Mexico, Albuquerque, NM, USA, 87131. Email: frantuzy@gmail.com