Sartre spells out what the imaginary means for an existential phenomenological ontology:
We are now at the point of understanding the sense and value of the imaginary. The imaginary appears 'on the ground of the world', but reciprocally all apprehension of the real as world implies a hidden surpassing towards the imaginary. All imaging consciousness maintains the world as the nihilated ground of the imaginary and reciprocally all consciousness of the world calls and motivates an imaging consciousness as grasping the particular sense of the situation. The apprehension of nothingness cannot occur by an immediate disclosure, it is realized in and by the free succession of consciousnesses, the nothingness is the matter of surpassing the world towards the imaginary. It is as such that it is lived, without ever being posited for itself. There could be no realizing consciousness without imaging consciousness, and vice versa. Thus imagination, far from appearing as an accidental characteristic of consciousness, is disclosed as an essential and transcendental condition of consciousness. It is as absurd to conceive of a consciousness that does not imagine as it is to conceive of a consciousness that cannot effect the cogito.
(The Imaginary p. 188)
If ontology is worth discussing then I too want to talk about how nothingness is lived. It's not that easy. When I examine my own experience of imagination I'm not sure whether I encounter anything like nothingness. Sartre says I don't apprehend it directly, but I'm unsure about the hidden surpassing towards the imaginary and whether that must proceed by a negation of the real world. If I accept that there is something like transcendence, does that really commit me to recognizing such an apprehension of nothingness? Most surpassings towards the imginary in my life are inchoate, and probably my grasp of the real is pretty loose. I desire a beautiful woman, which Sartre says I can't do; I am not routinely nauseated by the real.
A day went by. One of the days as the year dwindles down, neither belonging to the new year nor possessing the feel of the old, neither a holiday nor a workday, neither brilliant nor dismal. Staring out on the horizon, I might have been nauseated had I learned of a tsunami on the other side of the world, or an assassination. But there on that shore on that day I was not nauseated.
Indoors again, I imagined a trawler out on the horizon. In fact I imagined imagining a trawler on the horizon before I sat down and imagined one. I knew I would be confronting this issue of nothingness, trying to apprehend it, or what it means for the trawler as imaged to be absent. So my imagination of the trawler is suspect. And again, my imagination is not static. There is a crew on board the trawlers, characters. One of them is a Jack Kerouac-like figure peeling potatoes. Jack Kerouac was a romantic figure in my youth, yet he was also a real person who wrote stories about his friends and their travels. Everything about my imagination is suspect, infused with snippets of memory, culture, film, psychology, an ethos of compassion for all living things that is hard to live up to. What is the imagination itself? How would that differ from the imagination as it is lived?
I want to agree with Sartre that "the existence of a psychic phenomenon and the meaning it has for consciousness are one" (p. 19), yet I become aware that consciousness is something I must allow to happen, and that if I don't allow it to happen I am not really conscious, my conscious life has no meaning. Should I be nauseated at the discovery of a moment of meaninglessness? I have no reason to believe meaninglessness is benign. To feel its repulsiveness, though, I have to imagine this meaninglessness is Reality, or that the taste of nothing is really the taste of my own death, a death I am morbidly living. Morbidity may be the ultimate Neither/Nor, or the one we learn to live with. What then should we take from convalescence? It should be possible to imagine a meaningless one encounters as other than Real without being Irreal; it should be possible to recognize a situation as not yet having sense without meaning that one is therefore mired in or threatened by morbidity. Is the not-yet-sense of a situation really lived? Is the just-was-sense of a situation lived?
When I say that consciousness must be allowed to happen or that, pace Sartre, an imaginative consciosness may be surprising, while at the same time maintaining the Sartrean position against the existence of an unconscious that would bestow upon consciousness any meaning other than its own, it seems as if I must entertain the thought of a pre-existing morbidity, of a consciousness that is not all there, not healthy, not meaningful. This idea is perplexing because it is hard to fully grasp the truth that the not-yet-sense is pluripotent and senses are plural; we are not fully aware of the many ways we have of allowing consciousness to happen. The free succession of consciousnesseswhich must too be allowed, and which also may then have its senses and its non-yet-sensereveals neither nothingness nor a neither/nor that could be assigned to either morbidity or convalescence; rather it testifies to the abundance of consciousnesses, and that abundance is what's at issue in the as such. (It was a mistake, then, to think that allowance of a consciousness was preceded by a morbid consciousness.) This means that the cogito should not be conflated with the vivo, and one should avoid choosing one type of consciousness as a model for consciousness in general; the model of consciousness as it is lived is the free succession of conscious moments, and there may well be no consciousness in general or consciousness as such. I am taking a stand then against the existence of annihilation as such, and I am doing so on the basis of the abundance of the as such as such. I think we misrecognize the abundance of the as such as annihilation because fundamentally we identify consciousness with our vital existence. Well, to be honest, I would have an attitude about annihilation as such even if I weren't aware of the abundance of the as such. I am curious to know what it means to be conscious. It's still a little mysterious to me.