False consciousness

In Marxist usage, false consciousness means thought for which the underlying motives are incorrectly perceived by the thinker. The thinker supposes that the thought has arisen in her because of A, when in fact something else, B, is the actual cause.

The term was coined by Frederick Engels in 1893. He was expounding on the common historical materialist theme that the particular philosophy or ideology in vogue at a given historical place and time depends on the underlying material conditions of the society. This is rarely perceived, however, by the people there; they suppose their philosophy, etc. to have come about for other reasons, such as perhaps as a logical outgrowth of preceeding philosophies, theories, etc. in the realm of pure thought. In thus wrongly identifying the basis of their philosophy, the people are acting in false consciousness.

The following text is from Frederick Engels' letter of 14 July 1893 to Franz Mehring, in which the term "false consciousness" was first used:  Ideology is a process accomplished by the so-called thinker consciously, indeed, but with a false consciousness. The real motives impelling him [sic.] remain unknown to him, otherwise it would not be an ideological process at all. Hence he imagines false or apparent motives. Because it is a process of thought he derives both its form and its content from pure thought, either his own or that of his presecessors. He works with mere thought material which he accepts without examination as the product of thought, he does not investigate further for a more remote process independent of thought; indeed its origin seems obvious to him, because as all action is produced through the medium of thought it appears to him to be ultimately based on thought.