In the mirror stage, the hcild identifies with the specular iamge, and this inaugurates the series of identifications that will consturct the ego.
The child is literally captivated by a specular other thanks to an identification which is also an alienation.
The imaginary is thus the realm in which self and other merge, and in which identity is grounded in a mere semblance of unity.
The imaginary is not a stage which is overcome or transcended, and is a cosntant presence in the lives of human subjects.
It arises with the mirror stage but extends far into the adult individual's experience of others and of the external world.