Ideology is the one that makes essence of things throughout Ideology as a factor not of selfevolving but ''progress(-ivity'')
of
existence, as acting indepenedent of essence it has a purpuse this way of getting transformed, in terms of essence itself to a state, from which it gets, if not the ''gems'' of itself in hands, but uses idea, in order to produce its freedom..
Ideology is freedom. It's existence domination, over material, within goals it sets,-we mean the first one of course-, and freedom is the only way of Ideology fulfillment, as within it first of all its existence that's self-fulfilled. And while system mechanism is reproduced, existence is reproduced in the same way.
Freedom finds in ideology thae space of its selffulfillemnt, throughout existence itself, as this way, the essence of existence, is liberated, decoding things, and extracting that Idea, that will constitute, in its dimension of being, ''dominance'' of existence itself, by ''projection'' of Ideology on Freedm.
Therefore things get mature, for selffulfillemnt purpose, of existence inside ideas space, where Idea transcends material, and ''liberates'' ''Ego'' that instead of being ''condemned'' to live inside material, and fate of things, it rather lives within itself, (or rather would experience itself), within its reproduction, in a new form, of transformed material..
So, we are back to Sartre theory : finally the course from en soi to pour soi, (from in itself to ''for'' itself) is necessary, since existence cannot find an object of its motivation, if its not found beyond oneself and itself (of course, namely at ''en soi). Hence it makes the route from itself, to the essence of Being, to the ''pour soi''..Throughout Being out of itself, it get conscience of what is the object of its action as it has by any means to ''make the course (or route)'' so that it can find its substance and therefore ''fall to pour soi''(=the object for itself), to the Idealistic view point of things, exactly to find the field of its substantalism..