Put very simply ‘ideology’ is a system of ideas and ideals, particularly one that forms the basis of economic or political theory and policy. It can also be used to mean the ideas and way of thinking that are characteristic of a particular group or individual. The word took on a more recent meaning connected to a critique of bourgeois ideology and historically it grew out of the science of ideas and the study of their origin and nature. People who seem controlled by ideologies in uncompromising and dogmatic way are called ideologues
Jürgen Habermas has suggested that we might conceive of ‘ideology’ as arising when rational discourse breaks down and, indeed, that it is a way of concealing (and accommodating to) this breakdown. A prior question is also relevant: Why does rational discourse break down? Here we will mention only that this may happen when interests stifle discourse. That is, rational discourse is disrupted when it threatens the interests of the speakers, and it needs to be understood how very diverse these interests may be. Ideology, then, may be related to rational discourse on two levels: first as a kind of fraudulent discourse, a kind of counterfeit rationality that conceals the breakdown of rationality, on the one hand, and, also, as a concealment of the very forces that led to this breakdown, on the other. Ideology is thus both discourse—relevant and interest—relevant.
In contrast to ideology Gouldner proposes theory:
In contrast to ideology we counterpose ‘theory’. Social theory is rational discourse about the social world in that, on one level, it is deliberately seeking to advance certain interests in the world; it knows the interests that it advances, and provides an extraordinary language for rational discourse concerning these interests. On another level, social theory provides—as do Marxism or Freudianism—an extraordinary language with which men can become aware of the ideological usages of ordinary languages, and of the interests that these obscure and conceal. Theory, then, always has two sides: an establishing and affirming side, and an unmasking and polemical side. In one part, social theory seeks to say what is about the social world and, in another, it relates to ideologies about the social world, disclosing their meaning. A proper relation between theory and praxis, then, is not only one that advances praxis, but one that also advances theory as distinct from ideology.
Praxis means practice, as distinguished from theory, it’s from the Greek for ‘doing.’ Gouldner then makes some observations on how there are now almost no Communists, in the sense intended by Marx and Engels, because most of those who are called Communists (much the same applies to other movements) are deeply implicated in political groups that demand their primary loyalty. He then says:
It is precisely because a political organization has an interest that is invariably distinct and special, and is not reducible to the interests of the strata that it claims to represent, it is because it acquires a special interest even as it claims that it has no special interests, that such groups invariably foster an ideologization—a false consciousness—that undermines the rationality of discourse within them. It is this interest that generates ideology and undermines theory in political groups. Not that this is the only source of ideology in such political groups, but it is a necessary, inevitable and irreducible source of it. Which is another reason why theorists must have their own collectives.
For Gouldner the creative development of theory has a better chance when the theorists are related primarily to a diffuse movement rather than to a sharply boundaried loyalty-demanding organization.
This is exactly why the Critical School of Frankfurt was such a creative turning for Marxist theory. For, despite ambiguities in the political involvements of its members, the very existence of the Critical School itself served, if nothing else, as a counterbalance to whatever Leninist party attachments existed. That the Leninist tradition came to insist that ‘its’ intellectuals be tightly involved in the party structure and come under party discipline has been a major source of the ideologization of the Marxist movement, of the false consciousness of Marxist culture, and one of the fundamental organizational obstacles to the theoretical development of Marxism. Stalinism was only the grotesque intensification of the development that had preceded it.
For Gouldner the critique of theory and of intellectuals in such movements essentially consists of a critique of “open intellectuals by covert intellectuals who play the role of party leaders and organizational functionaries”. He sees this as a conflict among different kinds of intellectuals.
He offers five aspects of a conception of the role of the radical social theorist that he would encourage.
(1) The theorist as theorist should commit himself to the establishment of his own social collectivity, to know intellectually and to create practically the conditions requisite for rational discourse and human liberation, and within whose protection he and his fellows work toward the understanding of the concrete social totality with which they are historically faced. A ‘theorist’ is simply one who takes this as his primary human and political commitment, and his own primary way of contributing to human fulfillment. (An ‘intellectual’ we might say is a theorist who is actively interested in mobilizing and wielding power.)
(2) Theorists should positively seek out involvements with and on behalf of specific social strata and contribute to them and to social movements representing them in practical political ways, especially (and indeed, only) insofar as these strata are evolving in directions compatible with human emancipation.
(3) Theorists should engage themselves politically in ways that bring them into tension, conflict, opposition and resistance to established authority, institutions and culture, for these help them to escape from conventional definitions of social reality.
(4) The relations between theorists, on the one hand, and movements or parties, on the other, should be governed by the principle that each is autonomous of the other organizationally, but collaborate on the basis of their common commitment to human emancipation. Theorists should not wait to be asked for intellectual work or assistance by these groups, but should take initiatives in providing them. This should be done, however, without insisting on the political group’s use and, acceptance of, or commitment to, the theoretical collectives’ work. Theorists should seek no power, no office and no leadership in political groups, and they should reject full‑time political roles. Their primary engagement should be to their own theoretical collectivities, and if they undertake practical leadership roles in political groups they should resign their membership in their theoretical collectivity.
(5) Whatever their other political attachments, theorists should never submit to the discipline of any specifically political party or organization that believes itself entitled to discipline him on the basis of his intellectual products or work—that is, to control him as theorist, or to expel him from membership, on the basis of disagreement with his intellectual or theoretical work. That judgement should reside only in his own theorists’ collective.
Terry Eagleton’s (1991) Ideology: an introduction, (p. 154) offers a similar summary of Gouldner’s ideas on ‘ideology’; he also mentions the way ideology “masks the realities” of exploitation and domination in Bourgeois ideology, whereby it presents itself as “entirely innocent of power.” Interestingly Eagleton mentions the ‘end-of-ideology’ theorists as key exponents of this mask. Much the same summary is made in John B. Thompson’s (1990) Ideology and Modern Culture: Critical Social Theory in the Era of Mass Communication, (p. 84). Both of these texts explore the what-is-ideology question.
Eagleton lists definitions & approaches towards ideology: the ways the concept of ideology has been treated.
(a) The process of production of meanings, signs and value in social life.
(b) A body of ideas characteristic of a particular social group or class.
(c) Ideas which help to legitimate a dominant political power.
(d) False ideas which help to legitimate a dominant political power.
(e) Systematically distorted communication.
(f) That which offers a position for a subject.
(g) Forms of thought motivated by social interests.
(h) Identity thinking.
(i) Socially necessary illusion.
(j) The conjuncture of discourse and power.
(k) The medium in which conscious social actors make sense of their world.
(l) Action-oriented sets of beliefs.
(m) The confusion of linguistic and phenomenal reality.
(n) Semiotic closure.
(o) The indispensable medium in which individuals live out their relation to a social structure.
(p) The process whereby said life is converted to a natural reality.
Ideology is then abstract and false thought, in a sense directly related to the original conservative use but with the alternative — knowledge of real material conditions and relationships — differently stated. Marx and Engels then used this idea critically. The ‘thinkers’ of a ruling class were ‘its active conceptive ideologists, who make the perfecting of the illusion of the class about itself their chief source of livelihood’ […] This sense of ideology as illusion, false consciousness, unreality, upside-down reality, is predominant in their work. Engels believed that the ‘higher ideologies’ — philosophy and religion — were more removed from material interests than the direct ideologies of politics and law, but the connection, though complicated, was still decisive […] They were ‘realms of ideology which soar still higher in the air . . . various false conceptions of nature, of man’s own being, of spirits, magic forces, etc.
Max Horkheimer and Theodor W. Adorno are other key thinkers often cited here, and the Frankfurt Institute for Social Research that Gouldner mentioned, are also represented:
No matter how little lucidity these sentences may possess and how greatly the natural-right doctrine of the French Revolution is intermingled with a later physiology of consciousness, this much is clear, that Napoleon sensed in any sort of analysis of consciousness a threat to positiveness, which to him appeared more safely secured within the heart. The later usage too, which employs the expression “unworldly ideologues” against allegedly abstract utopians in the name of “Realpolitik,” is discernible in Napoleon’s pronouncement. But he failed to realize that the ideologues’ analysis of consciousness was by no means so irreconcilable with the interests of the rulers. Already then a technical manipulative moment was associated with it. The positivistic doctrine of society never divested itself of this, and its findings were always utilizable for opposite aims. For the ideologues too the knowledge of the origin and formation of ideas was a domain for experts, and what these experts do is to provide the legislator and the statesman with the ability to establish and preserve the order desired by him, which, to be sure, at this point is still equated with a rational order. But the conception that by a correct knowledge of the chemistry of ideas one can control men, still predominates; and in the face of this, the question of the truth and objective evidence of the ideas becomes secondary, in keeping with the skeptical turn of mind by which the school of the ideologues was inspired; and so does the question of the objective historical tendencies on which society depends, in its blind “natural lawlike” progress, as well as in its potential for a conscious rational ordering.
 Gouldner, Alvin W. For Sociology: Renewal and Critique in Sociology Today(New York: Basic Books, 1973), chapter 4, “The Politics of the Mind”(82-127), section titled “Theory and Ideology”, pp. 115-123.
 Semiotics are the study of signs and symbols and how they are used and interpreted.