Karl Mannheim quotes:

A modern theory of knowledge which takes account of the relational as distinct from the merely relative character of all historical knowledge must start with the assumption that there are spheres of thought in which it is impossible to conceive of absolute truth existing independently of the values and position of the subject and unrelated to the social context.

The distrust and suspicion which men everywhere evidence toward their adversaries, at all states of historical development, may be regarded as the immediate precursor to the notion of ideology.

[W]hen the empirical investigator glories in his refusal to go beyond the specialized observation dictated by the traditions of his discipline, be they ever so inclusive, he is making a virtue out of a defense mechanism which insures him against questioning his presuppositions.

All knowledge is oriented toward some object and is influenced in its approach by the nature of the object with which it is pre-occupied. But the mode of approach to the object to be known is dependent upon the nature of the knower.

As long as one does not call his own position into question but regards it as absolute, while interpreting his opponents' ideas as a mere function of the social positions they occupy, the decisive step forward has not yet been taken.

At this point in history when all things which concern man and the structure and elements of history itself are suddenly revealed to us in a new light, it behooves us in our scientific thinking to become masters of the situation, for it is not inconceivable that sooner than we suspect, as has often been the case before in history, this vision may disappear, the opportunity may be lost, and the world will once again present a static, uniform, and inflexible countenance.

Behind every rational and irrational force in human society there is a social mechanism which determines where it is to appear and what forms it is to take.

For progressive people the present is the beginning of the future. For conservative people the present is the end of the past.