Immanence is im-mediate in the sense that it is not mediated by language, trace, notation, history. This is a strong claim, but it’s purpose is to discover a stance that can defend humans against the harassment (often violent) of all these mediations (this is the salvific intent of non-philosophy). Laruelle is trying to show up the “weak power” of an indifference to all those mediations, a non-acting with regard to them as ‘sufficient’, an indifference that is immanent in ‘silent simple human/generic presence’.
However, if I could put it this way, all those things just named (which all ‘transcend’ in some fashion) are “caught up in” or “fall into” immanence (obviously, otherwise we’d have no presentation of them, they would be transcendences beyond our access).
The immediate of immanence would not be an absolute negation of mediation (as if it could be done away with, by magic or fiat or theory), nor of its relative power in the world wherever it functions. But it would/could/does undermine and *under-determine* mediation. It robs it of its power over the lived experience of a subject, robs it of its priority. The idea is to access an “immediate human immanence” that could serve as an ‘a priori’ resistance to the violence of all these mediations (see General Theory of the Victim).
One precaution to raise here: immanence is not the “immediate” consciousness of a self or whatever, definitely not to be confused with sense-certainty. One of Laruelle’s way to say this is that radical immanence “pre-empts” the lived of the subject. It is come before anything (any X) comes, it is “defined” only by this pre-emption. It is generic instead of individual or subjective. It comes underneath existence or under-comes, and is never reducible to the movement of being, to a localization in beings, not reducible also to an atomistic and/or corpuscular model of the universe, nor to “philosophy” with its circles of transcendence (world, history, being, etc.) and all that they imply in terms of mediations (identities, individualities, histories, languages, etc.). Thus the need eventually to discuss immanent fluxes, waves of virtuality, etc. in order to get at the indeterminate nature of what is “immediate” (and again, not immediate like an object or a thing, but immediate like the crest and trough of a wave– not the wave crashing against something, but the form-movement that it is).
I think we know this experience of an immanence outside the world or outside time (sometimes we feel this when we fall in love or have a flash of insight). Put stupidly, I’d say Laruelle is trying to get at a theory of this split-second surprise happening (“the Last Instance”) that always in one way or another escapes the encapusulating and capturing mechanism of exterior mediation.
This is where the logical tools like “unilateral duality” come in handy. Immediate immanence is not mediated and yet it is capable of “mediating” mediations (not just interpreting, but debasing, deprioritizing). For Laruelle immanence can transform/determine transcendences but transcendences do not determine immanence. It’s one-directional from immanence to transcendence, and this comes as a message of salvation. The composite in theory thus ends up having to be called a “mediate-without-mediation” (the Messiah) : immanence can mediate all this, but in its immediacy nothing mediates it, it “escapes” every capture by transcendence and keeps ascending.