I'm not sure what I mean by "the left". What I intend to point to is not a homogenous theory, but rather all that thinking that involves bringing together Marx, Hegel, Freud, Nietzsche, et al. I might point to Sartre or Zizek as famous examples----but then I'm not trying to describe only Zizek's theory of the self, object...etc.
I'm an atheist, but what I'll get to is the best possible (to my mind) argument in favor of a not so horrible god or gods, or whatever---just there is a creator and it doesn't completely hate us.
The left often teaches that self-awareness is originated in a kind of ontological/psychological/developmental trauma at some point in infancy. At birth we are not aware of ourselves, but later we are aware of ourselves. That change is traumatic. In the transition we find ourselves but we also find the other, "the other" being the correlative of the self. The object is also originated here, the object as such being just anything that is not-me.
Before I come to self-awareness my desires and their fulfillment are one and the same. My non-self, my self before it is aware of itself, does not, cannot, distinguish between a desire and its fulfillment. It is hard to flesh-out the experience of a non-self-aware human, but that is what is required. Julia Kristeva calls it the "chora" (eg
http://goo.gl/ygTjZb ,
http://www.jstor.org/stable/3810844). Within the chora desires and their fulfillment are seamless, which is very very nice for me. A warm OM. No 'me', no other, no questions, no answers, no work, no drama.
However, eventually I arrive at myself. There is an experience of difference, a gulf between my self and all things (that gulf is grounded in the fact that there is now a gulf between myself and myself---see Hegel's notion of "self-othering" in the Phenom., et al). Suddenly there is an other out there who delivers the fulfillment of my desires (think mouth to breast), I am dependent on them. Desire and its fulfillment are divorced when I become aware of my self. They might be cobbled together again . . . but it all depends. This new element of dependency and difference, a space, a void, a presence of an absence, between my self and the fulfillment of my desires is a shock---an ontological/psychological shock. It's a shock, some might say, we are never done working through. Even if one is of 'perfect' health psychologically, there is still the problem of selfhood to work through. The origin of the self then is necessarily at the very same time the self's introduction to the negative, to nothingness. Me, the negative, the other, the object---they are conjoined twins born at the same time.
Our "tarrying with the negative" does not begin within some exquisite existential event, it begins with you at the very moment you become self-aware. My very own self is the embodiment of the shock of the negative. There is no happy place at the core of my being.
Now the problem with the left's shock theory described above is this: we are not *thrown* into the world; or rather, I'm not thrown into my self-awareness. Empirically speaking, the development of my self-awareness is so very extremely, ridiculously slow it makes the precise location of the origin of self-awareness impossible. And that's it! The benevolence, the god part. We aren't thrown, we're smeared---verrrrry sloooowly smeared. Smeared with love. Smeared into the world so slowly that the trauma that ordinarily attends the introduction of difference is avoided.
I'm still an atheist, and in the end I actually think we're thrown. Thrown because one can actually recover the shock of the introduction of difference (see Sartre's Nausea, for instance). Though, it sure looks like we're smeared. Like I said at the beginning, I don't find the smear theory persuasive, it's just the "best possible" argument