The writings of Walter Benjamin include appropriations and transformations of modernist architectural history and theory that offer an opportunity to broaden the interpretation of how the relationship between the 'unconscious' and technologically aided 'optics' is figured in his commentaries on cultural modernity. This essay focuses on three moments in his writings, each of which touches on this topic in a different way: first, on Benjamin's reading of Carl Bötticher's theory of architectural tectonics as a theory of history in which the unconscious serves as a generative and productive source that challenges the existing matrix of representation; secondly, on Benjamin's transformation of Sigfried Giedion's presentation of iron structures into optical instruments for glimpsing a space interwoven with unconsciousness, a new world of space the image of which had seemingly been captured by photography; and thirdly, on Benjamin's suggestion that the mimetic faculty continues to play within representation, history and technology to produce similarities between the human and the non-human. In each instance, Benjamin reworked the dynamic dualism of nineteenth-century architectural tectonics - (self)representation seeking reconciliation with alterity - into a dialectic. In so doing, he set the cause of revolution (of a modernity yet to come) against metaphysical and utopian claims, progressive and regressive alike.