Most theory describes something. Max Horkheimer's question was what a theory is doing — who produced it, from what position, and in whose interest it happens to be true.

That sounds like an accusation and is meant as a discipline, including on itself. It is the demand he put at the center of the Institute for Social Research when he took it over in 1930, and it is still uncomfortable, because almost no piece of work is written in a way that could answer it.

Traditional and critical theory

The 1937 essay of that title is the founding document of the whole school, and the distinction it draws is sharper than its reputation.

Traditional theory takes itself to stand outside what it studies. It gathers facts, forms hypotheses, tests them, and treats the theorist as an observer whose own situation is irrelevant to the result. This is the model of the natural sciences and it is entirely appropriate there.

Critical theory denies that a social theorist can occupy that position. The theorist is inside the society being described, formed by it, paid by some part of it, and thinking in categories the society supplied. A theory of society that leaves out its own conditions of production has omitted one of its objects.

So the demand is reflexive: a theory must be able to give an account of why it exists. Not a confession of bias, which is cheap, but a structural account — what arrangement produced the question, and what would follow for the theory if the arrangement changed.

The further claim is that this changes what theory is for. Traditional theory aims to describe accurately; critical theory aims at emancipation, and treats a description that leaves everything as it is with suspicion rather than as neutral.

Instrumental reason

The second contribution is the diagnosis that followed him for thirty years, and Eclipse of Reason (1947) is its clearest statement.

Reason, on his account, used to be asked what ends were worth pursuing. It was capable of judging purposes, and philosophy from Plato onwards had assumed so. What replaced it is reason as an instrument: extraordinarily good at working out how to get something, silent on whether it should be got.

Once reason cannot evaluate ends, ends come from somewhere else — from interest, from power, from whatever is already established. Efficiency becomes the only value that can be argued for, because it is the only one left that reason recognizes. A society can then be perfectly rational in every procedure and have no way at all to ask whether what it is doing is worth doing.

That argument is worked out at book length with Adorno in Dialectic of Enlightenment, which is where the culture industry analysis lives and where it should be read.

The difficulty with the program

The objection is the one his own method invites, and Habermas made it from inside the tradition.

If reason has become wholly instrumental, what kind of reason is the critique using? The argument seems to saw off the branch it is standing on: to show that reason cannot judge ends, it has to judge one. Horkheimer's later work grew steadily more pessimistic about this and eventually stopped offering a way out, which is honest and is also why the second generation had to rebuild the foundations.

Habermas's answer was communicative reason — a form of rationality located in the conditions of unforced agreement rather than in the control of objects. Whether that rescues the program or abandons its severity is the central dispute inside critical theory.