When I was in graduate school "the imaginary" was one of those words that circulated all the more often because it was untethered to any specific theoretical source. It borrowed bits from Lacan and bits from Castoriadis to suggest some historically specific articulation of the very capacity to imagine. There were multiple imaginaries, political, social, technical etc., As someone who was getting interested in Spinoza at the time I tried to connect his writing on the imagination with this idea to no avail.
Now, thinking about Spinoza again, it might make sense to think about the way in which Spinoza's particular idea of the imagination is useful for thinking about social and political life. I should be clear that on this point I mean "imagination" as it is described as a particular kind of necessarily incomplete and inadequate knowledge in the Ethics, and not superstition as it is developed in Spinoza's political writings. Any such separation is artificial, as the two are thoroughly intertwined as bodies and minds, however, it is still worth at least heuristically the limitation of thinking from that of acting.
For Spinoza the imagination, images formed by the body, always involve both the body that affects us and how we are affected. As Spinoza writes,
"Next, to retain the customary words, the affections of the human body whose ideas present external bodies as present to us, we shall call images of things, though they do not reproduce the figure of things. And when the mind regards bodies in this way, we shall say that it imagines." (EIIP17schol).
It is not representation but presence that is central to the imagination. To imagine something is to regard i as present. This presence is a confused amalgamation of the qualities of the thing affecting us, and the way we are affected. To imagine is to treat our own associations and connections as if they were part of what we are perceiving.
"For example, a soldier, having seen traces of a horse in the sand, will immediately pass from the thought of a horse in the sand will immediately pass from the thought of a horse to the thought of a horseman, and from that to the thought of war and so on. And so each one, according as he has been accustomed to join and connect the image of things in this or that way, will pass from one thought to another" (EIIP18Schol).
As I have argued in my post on Spinoza and conspiracy theories is that it stresses the imagination can be both complex, involving a chain of associations from hoof print to horse, and horse to war, and immediate, directly lived as something present. As Althusser stresses for Spinoza the imagination is nothing other than the phenomenological world of lived experience as such. All of our perceptions and evaluations of the world as it is lived, or tendency to view some aspects of nature as good or bad, useful or harmful, organized or disorganized, are the imagination, which is to say are confused perceptions of our own desires and the way that the object affects us.
I was thinking of this mediation of the immediate or the immediacy of mediation when reading about theories of race. First, and not surprising, is this line from Etienne Balibar's "Is there a Neo-Racism?" As Balibar writes "I shall therefore venture the idea that the racist complex inextricably combines a crucial function of misrecognition (without which the violence would not be tolerable to the very people engaging in it) and a ‘will to know’, a violent desire for immediate knowledge of social relations." In other words, part of the appeal of racism is that it makes social relations immediately legible. It provides a geography, dividing town into the "good" and "bad" part, a morality, telling us (people who believe ourselves to be white) who to trust and who to fear. As much as this imagination is immediate, registered in somatic markers such as skin, hair, and eye color, the immediacy is a product of associations and connections that we are constantly subject to, media, entertainment, etc., and, like Spinoza's soldier, we have forgotten in focusing on the immediate present nature of the image.
Or, to take another version of the argument, this time from Stuart Hall,
"Race is only one element in this struggle to command and structure the popular ideology: but it has been, over the past two decades, a leading element: perhaps the key element. Since it appears to be grounded in natural and biological "facts," it is a way of drawing distinctions and developing practices which appear, themselves, to be "natural," given and universal...Race provides the structure of simplifications which make it possible to construct plausible explanations of troubling developments and which facilitates the application of simplifying remedies. Who now wants to begin to explore the complex of economic and political forces which have perpetuated and multiplied the poverty of the working-class districts fo the inner cities? Who will have time for that complicated exercise--which may require us to trace connections between structures of our society which is more convenient to keep apart: when a simple, obvious, "natural" explanation lies to hand."
A few hasty connections/conclusions. First, if you listen to any episode of Hotel Bar Sessions the podcast that I am now a cohost of, I suggest you listen to the interview with Caleb Cain available here (I can plug this in good faith because this is from before I joined the show):
One of the thing that comes up in the discussion is how the racist, or "race realist" explanation offers a quick an easy explanation of a variety of phenomena, such as why the inner city of Baltimore is the way that it is in terms of poverty and crime. An actual, or to use the Spinozist term, adequate understanding of the actual factors that have made the inner city the way it is would have to take into consideration the history of slavery, Jim Crow, redlining, deindustrialization, etc. etc. etc., Of course it is important to point out that what appears here as immediate, race as an explanation, is itself the product of a long history of associations. It took us a long time to see race, and it takes a lot of work, political and ideological, for us not to see everything about social life, the accumulation of capital, and so on, that is effaced in the immediacy and simplicity of seeing race.
So this is what it might mean to consider what "the imaginary institution of society" might mean from a Spinozist perspective. It is the dominance of a particular set of immediate associations of bodies and qualities, associations that are themselves the product of a complex articulation (in Hall's sense), that disappears in the immediacy of the association. I have focused here on race as one such mediated immediacy. It would be wrong to think it is the only one. As Alexandra Minna Stern argues in her book Proud Boys and the White Ethnostate: How the Alt-Right is Warping the American Imagination, "Transphobia is the butter on the bread of much alt-right and alt-light vlogging." As with race there is an appeal to a kind of natural immediacy, that of sex, gender, and gender roles, one that is the product of many mediations, right down to the latest explosion in a gender reveal party. The natural order of sex and gender is in some sense the entry point to a larger sense of a natural order. Of course the relation between these two different images of nature, racial and sexual, is complex, overdetermined, and in some sense always shifting.
As much as there is an epistemic tendency towards the imagination predicated on its immediacy and self-evident nature, there is a practical one as well: the order and connection of bodies being the same as ideas and all. For many, especially those with advantages in the existing order, there are reasons to hold unto and act within the horizon described by its imagination. I recently finished reading Jeremy Gilbert and Alex William's Hegemony Now: How Big Tech and Wall Street Won the World (and How We Win it Back). In the midst of that book there is a long discussion to retrieve the idea of interests in politics. One of the things that Gilbert and Williams stress that one's interest is related to both one's position and one's horizon. As they write,
"From this perspective, workers who vote for immigration restrictions are acting against their interests when conceived within a liberal, communist, or even expansively social democratic horizon, but not when conceived within a conservative horizon. What is it that defines the particular characteristics of the horizon within which interests are perceived, computed, and acted upon? In part it must be a question of the scale--in terms of space and time--of that horizon. When horizons of interest are operating at a small scale, this will mean a focus on the hyperlocal (my immediate family) and the hyper-present (today and tomorrow and perhaps next year). What is reasonable within one horizon is unreasonable in another."
If we want to change and expand the horizon of people's interest we must first recognize the horizon that they already operate within even if that horizon is defined by imaginations that seem irrational to us. "Inadequate and confused ideas follow with the same necessity as adequate, or clear and distinct ideas" (EIIP36). To put this in Spinozist terms, we all strive to maintain our existence, but we do so according to what we understand, rightly or wrongly, to be in our interest according to our given level of imagination or understanding. All of which is a very long way of saying that any politics of radical change has to start with understanding the epistemic and practical attachments that most have to the existing imaginary institution of society.