Part 4 has covered six topics and forty-three lessons. Before Part 5 takes up the schools that grew out of this material, it is worth stopping to do an accounting: what did the founders actually build, where do they disagree, what did they get wrong, and what could they not see from where they stood?

This lesson is a synthesis rather than a new argument. Its purpose is to leave you with a map you can use.

What they built: the inventory

And four methodological inheritances, which matter as much as the concepts:

The empirical demand. That sociological claims must be checkable. Durkheim's rules and Suicide; Du Bois's Philadelphia survey; Hull-House's maps; Weber's insistence on causal adequacy.

The comparative method. Explaining a case by systematic comparison with cases lacking the outcome. Weber's religion studies; Durkheim's concomitant variation.

The interpretive requirement. That human conduct cannot be identified, let alone explained, without knowing what it means to those doing it. Weber's Verstehen.

And the reflexive turn. That a discipline's own categories, canon and blind spots are legitimate objects of study. Marx on ideology; Du Bois's "Propaganda of History"; Alatas's captive mind.

Where they disagree: the map

What they got wrong

An honest list, drawn from the individual lessons.

What they missed

The more important list, because these are not errors within a framework but things the frameworks could not register.

Gender

The colonial relation

Du Bois excepted, the founders analysed modernity from inside the imperial metropole and treated empire as background, as a stage, or as comparison cases (4.5.3, 4.6.3). If modernity was constituted by the relation between Europe and the colonised world, then a theory built only from the metropolitan end misdescribes its object. Part 6 is the correction.

The environment

Marx's metabolic rift (4.1.9) is the one substantial exception, and it was buried until the 1990s. Otherwise the founders analysed a world of apparently unlimited natural inputs. A theory of society that treats the biosphere as a background condition rather than as a constraint is missing something that may turn out to be the binding one (11.5).

The body, disability and age

Almost entirely absent as analytical categories. Health appears as mortality statistics; the body appears in Simmel and in Weber's asceticism as a site of discipline; disability does not appear at all; age appears only in Durkheim's demography.

Emotions

Weber's affectual action is a residual category at the "borderline" of meaningful action (4.3.2). Durkheim's collective effervescence is the exception and was not developed until Collins (4.2.6). The sociology of emotions had to be built almost from scratch from the 1970s.

And scale

None of them could analyse a world in which a single firm employs more people than most of the states they studied, in which a communication system reaches billions instantaneously, or in which the relevant unit for many questions is planetary. Their instruments still work; the objects have changed size.

Go deeper

The three big unresolved problems

Part 4 leaves three questions open, and they organise the rest of this course.

Structure and agency (1.3.1, and Part 13). Durkheim's constraint against Weber's meaningful action; Marx's "men make their own history, but not under circumstances of their own choosing"; Simmel's dissolution of the dichotomy into process. No founder resolved it, and the twentieth century's major theoretical projects — Giddens's structuration, Bourdieu's habitus, Archer's morphogenesis — are all attempts (5.10, 5.11).

Consensus and conflict (1.3.4). Durkheim's solidarity against Marx's contradiction, with Weber's legitimacy and Simmel's conflict-as-sociation between them. Part 5 is substantially organised around this split, and its resolution is generally that both are describing real features and the interesting question is the conditions under which each predominates.

Material and ideal (1.3.6). Marx's base against Weber's Protestant ethic, with Durkheim's collective representations and Simmel's money form on different ground again. The mature position is that the question "which comes first" is badly posed, and that what is wanted is an account of how the two are related in specific cases — which is what elective affinity, hegemony and the sociology of knowledge are all attempts at.

How to read a founder, as a general procedure

Part 4 has applied a consistent method, and it is worth stating as a transferable procedure.

And a word about what this Part is for

The founders are not authorities. They are the people who built the instruments, and the instruments are better than any of the people who built them.

Reading them is not a matter of deciding who was right. It is a matter of acquiring a set of questions that can be asked of anything — a workplace, a family, a queue, a riot, a market, a religion, a database — and of knowing which question to ask when.

And it is a matter of learning what a discipline looks like from inside: how it decides what counts, whom it reads, what it forgets, and how long it takes to notice.

Why it matters

You now have a toolkit rather than a reading list. Twenty-four questions from six positions, each with a specified domain of strength and a specified failure mode. That is the practical deliverable of Part 4.

You have a map of the disagreements, which is what makes Part 5 legible. Functionalism, conflict theory, interactionism and critical theory are not four arbitrary schools; they are four developments of positions staked out here.

You have a method for reading any thinker: establish the publication history, state the strongest version, check the evidence, separate what survives, state the political history, and ask what the position could not see.

And you have the discipline's most uncomfortable finding about itself. Four times in this Part — Martineau, Du Bois, the Chicago women, and the traditions outside Europe — the same pattern: work produced, published, available, unread, and rediscovered decades later. A field that studies how institutions shape knowledge has to be willing to apply that to itself, and Part 4 has tried to.