The functional theory of stratification holds that ranked inequality is not an accident of history or a residue of conquest but a functional necessity — something every society must have because every society faces the same problem. The problem, as Kingsley Davis and Wilbert Moore stated it in 1945, is one of role allocation and role performance: a social system must distribute its members among the positions its division of labour requires, and must then induce them to discharge the duties of those positions. Since positions are not equally attractive, equally important, or equally easy to fill, societies evolve schemes of differential reward attached to positions rather than to persons.

Stratification, on this reading, is the unintended consequence of a motivational device. It is the by-product of the need to place people, not a conspiracy to keep them in place. Davis and Moore were explicit that they were explaining the existence of unequal positions, not the justice of any particular distribution, and that the rewards in question fall into three families: sustenance and comfort (income), humour and diversion (leisure), and self-respect and ego expansion (prestige).

The two determinants of rank

Two variables fix how much reward a position must command. The first is functional importance: how far the tasks of the position are indispensable to the working of the whole, and how far other positions depend upon it. The second is the scarcity of qualified personnel — the size of the eligible talent pool and the burden of the training required to convert talent into competence. A position of high importance that anyone can fill needs little inducement; a position requiring long, costly and self-denying preparation needs a great deal, because the sacrifice of years of earning and pleasure must be compensated.

From this Davis and Moore derived their ranking of institutional spheres. Religion, government, economy and technology each generate high positions, but the mix of reward differs: priestly roles are compensated heavily in prestige and lightly in income, entrepreneurial roles the reverse. The scheme thus predicts not merely that inequality exists but roughly where the peaks will be.

Tumin's rebuttal

Melvin Tumin answered in 1953 with a critique that has become as canonical as the thesis. Its force lies in taking the argument apart proposition by proposition.

First, functional importance cannot be measured independently of the reward it is supposed to explain. We infer that a position matters because it is well paid, then explain the pay by the mattering — a circle. Tumin's illustration is the factory: are engineers more indispensable than the unskilled workers without whom nothing is produced? Indispensability is a matter of the whole configuration, not of single roles.

Second, the theory assumes an accurate reading of the pool of talent, whereas stratified societies systematically waste talent. Access to training depends on the resources of parents, so the discovery of ability is truncated at the outset. Stratification is therefore not a device for finding talent but a barrier to finding it, and existing élites function as self-recruiting groups that restrict entry to protect their own children.

Third, the account of training as sacrifice is doubtful. Periods of training are often subsidised, carry prestige of their own, and are followed by a lifetime of differential return far exceeding any loss. Fourth, alternative motivations exist: intrinsic satisfaction in the work, the joy of duty, social service, and prestige unaccompanied by wealth all move people, as the reward structures of armies, monasteries and academic life suggest.

Fifth, and most damaging, stratification is dysfunctional. It distributes unfavourable self-images among those placed low, limits the expansion of a society's productive resources, sets hostility and distrust between segments, and weakens the loyalty of those who receive least. Finally, Tumin identified the ideological function of the theory itself: a doctrine that inequality is necessary is precisely what the advantaged require, so the theory risks becoming a scientific dress for privilege — a charge sharpened by the fact that Davis and Moore wrote of positions while their argument was read as being about persons.

Caste as the decisive counter-case

The clearest empirical difficulty is the caste system. Here reward is attached not to achieved position but to birth: the son of a priest is a priest, the son of a scavenger a scavenger, and the question of inducing the ablest to undertake training does not arise because occupation is not open. If the functional theory were right, such a system should perform badly and be short-lived; instead it endured for centuries. Worse, caste inverts the theory's logic — ritual rank and economic reward come apart, so that the Brahmin may hold the highest prestige without the highest income, while the dominant caste of André Béteille's Sripuram holds land and power without the highest ritual standing. Ascription, not the market in talent, does the allocating. Davis and Moore might reply that ascriptive systems are merely inefficient variants; the reply concedes that the theory explains far less than a universal functional requirement should.

The Indian merit and reservation debate carries the same argument into policy. The claim that reservation sacrifices efficiency to representation rests on a Davis and Moore premise: that examination scores index functional capacity and that unequal reward is the price of competence. The counter-claim rests on Tumin: that when families differ enormously in schooling, language, nutrition and confidence, a score measures accumulated advantage as much as ability, so reservation widens rather than narrows the pool from which talent is actually drawn. The debate is thus not incidental to the theory but a live national argument about its central assumption.

For the UPSC answer

Present Davis and Moore as a genuine problem-solution argument — the problem of role allocation and performance, solved by differential reward calibrated to functional importance and scarcity of personnel — before you criticise it, since examiners reward a fair statement of the thesis. Then run Tumin point by point: measurement circularity, wasted talent, stratification as a barrier to discovery, implausible sacrifice, alternative motivations, dysfunctions, and ideology. Use caste as the counter-case that ascription defeats the model, noting the divergence of ritual status from economic reward. Close by connecting the controversy to the Indian merit debate, which shows that the theory is not an antique dispute but a template for arguments still being made.

References & further reading

  1. Davis, K. and Moore, W. E. (1945). Some Principles of Stratification. American Sociological Review, 10(2).
  2. Tumin, M. M. (1953). Some Principles of Stratification: A Critical Analysis. American Sociological Review, 18(4).
  3. Tumin, M. M. (1967). Social Stratification: The Forms and Functions of Inequality. Prentice-Hall.
  4. Parsons, T. (1940). An Analytical Approach to the Theory of Social Stratification. American Journal of Sociology, 45(6).
  5. Béteille, A. (1969). Castes: Old and New. Asia Publishing House.
  6. Bendix, R. and Lipset, S. M. (eds.) (1966). Class, Status and Power. Free Press.