a signifier whose contents are unknown.
Lacan repeatedly emphasises the extent to which we are dominated by the presence of such signifiers. This is a way of thinking that has no room for notions of ‘objective reality’ or ‘autonomous ego’. At the heart of the subject there isn’t autonomy but ‘submission’ to language. Or, in the optical metaphors at the heart of the subject, there isn’t a ‘self’ but a mirror reflecting a mirror.