Had the pleasure of attending a screening of this recently. I'd only seen it once, and that was years ago. Don't think I had any idea what to make of it then, but upon seeing it again, mulling it over and doing some reading I arrived at a core interpretation which, while naturally subjective and partial, feels pleasing. There's a huge richness of potential symbolism and subtext in this film! Many valid interpretations are available, so it's a very fun one to ponder. Tarkovsky also, so far as I understand, refused to be drawn very far regarding what any of it meant. Allegedly^[1] he took the position of "I don't do symbolism; I do story". But he also said:

In summary, my reading is that the film is about spiritual crisis caused by belief in the primacy of concepts and ego. The dangers of perceiving totalising conceptual frameworks as having primacy (seeing them as a possible means of directly engaging with experience, losing sight of their inability to provide ultimate answers), and the dangers of strong identification with ego.

Each of the three main characters represent a mode of engagement with experience, and each have some sort of unhealthy egoic relationship with their mode.

The Stalker represents the truth-seeking of religious institutions and faith. For him, the Zone is a divine site and each incursion is a pilgrimage. But understanding and interacting with the divine via the abstraction of a conceptual framework (the rites and rituals of Zone traversal, the Zone as a holy site) cuts him off from direct experience of it, because he has confused the map for the territory - direct, preconceptual experience is the only way we can actually apprehend the divine. So, he has come to identify with the role of helping others to experience it, as this is the closest he can get. But because of this self-serving element his motivation cannot be truly compassionate. This is why he never enters the Room - on some level, he always knew that his motivation was impure. And why he becomes so distraught when the Writer calls him out on it, and with people's inability to get what he thinks they should out of Zone pilgrimages. He's experiencing a total crisis of meaning. Already his faith was in question, because he'd cut himself off from divine experience. Now he can't even consciously deny the impurity of his motives in helping others to access such experience. And yet we get "Calling themselves intellectuals... they don't believe in anything!" because he still cannot integrate these things. He can't accept that his reification of concepts and belief is exactly the problem.

The Writer represents the truth-seeking of the arts. He's on an impossible quest to truthfully represent direct experience in conceptual/linguistic terms. This provides him with the identity of a tortured artist, and the material and social success which come with it. He's the boldest of the three, the only one who's able to confront the inadequacy of his framework, even though his remaining attachment to ego continues to prevent him from accessing transcendence. He does at least realise that he should not enter the Room, because it'd only end as it did for Porcupine. So he'll go and continue the bit of the "tortured artist" identity he can still manage (the actual writing now being understood as pointless, because it cannot access truth), by drinking himself to death in his mansion. He's seen through the false pretence he was labouring under, but still can't make the leap into unknowing that moving past it calls for.

The Scientist represents the truth-seeking of rationalism, and is attached to a rationalist metaphysical mode of understanding due to a need for existential certainty. But, he finds that he's so attached to it that he can't bear to enter the Room even with the goal of destroying it. Whatever he might find in there is such a threat to his worldview, and thus his identity, that he can't bear to confront it. We learn that even amongst his colleagues he's particularly dogmatic when he makes a gloating phone call to boast about having found the bomb which they had reconsidered the use of. This also displays his egoic need to maintain the legitimacy of rationalism - it was never about humanitarianism, as he claimed, but about his ego. If he had an experience in the Room which could not be accounted for by his worldview, it would destroy his perceived legitimacy of that worldview, and thus himself - a philosophical/egoic death.

This is why only the "wretched" can have a non-negative outcome from visiting the Room. They've accepted that divinity, or truth, cannot be apprehended via concepts or ego, and so have given up the search. In this they have found what they were looking for, or at least stopped grasping for it and gotten comfortable with simply not knowing. Which wouldn't leave any desire to use the Room anyway - either way, like Monkey, these people have already achieved transcendence. The Room would perhaps do nothing at all for them. As the Writer points out, we don't know that anyone except Porcupine has ever entered it.

Monkey is one of the "wretched". She does not reify a conceptual framework or ego (she seems to be characterised as little as possible) in order to mediate experience. The divine is thus accessible to her without any need to go anywhere, or do anything. She's simply being, and thus is not getting in her own way.

So the Room could be a spiritual trap. It represents an ultimate reification of concepts and ego - follow these proscribed rites and rituals, and you can access divinity, whatever that means to you. There's no need for any kind of spiritual alchemy - come as you are. But anyone "wretched" enough to experience a non-negative outcome from visiting it would have no interest in doing so. Anyone who would wish to use it should not, because their relationship to experience and ego is guaranteed to be perverse, and the Room will punish that by giving them exactly what they want.

Or the Room just is, and it's the main characters who make it into a trap by interacting with it via ego and frameworks. In this way it could be similar to existence itself - the trap of identification has already been sprung^[2], and the hope and anguish inspired by the Room, one representative symbol among many, are merely symptomatic of this. Resolving ignorance via direct knowledge of what's happening removes any danger, and we discover that all this suffering was self-inflicted.

If the three could only stop striving, they would find the same peace Monkey has. This invites some delicious, maddening, and familiar to those on the path spiritual paradoxes. How can one end striving, without striving to? How can one deconstruct ego, from within ego? These are all soluble, but not in a way that makes conceptual sense, because experience and divinity are themselves not conceptual.