The honest answer is no, and I don't think that's as tragic as it sounds. Every person contains vastly more inner life than any other person will ever access. Even the closest partners, after fifty years, are still occasionally surprised by each other. The parts of you that you haven't told anyone — including the ones you've never articulated to yourself — are always going to outnumber the parts you've shared.
What we can do instead is trust the shape of another person, even when we can't see all of it. You learn the pattern of someone's reactions over years, and you can predict roughly what they'll say about a new situation before they say it. That's not knowing them. It's building a model of them, imperfect and provisional, that's usually good enough for the daily work of being close to them.
The trap is mistaking the model for the person. When a long relationship goes stale, it's usually because both people have stopped updating their models of each other, and each is now in a relationship with a slightly outdated version of the other. The person kept changing. The model didn't. The corrective isn't to know the other person completely, which is impossible, but to keep asking questions as if you didn't already know the answer — because you probably don't, anymore.
Also worth a look: https://20260713-lice-treatment-lc.pages.dev/22-why-portland-parents-choose-professional
The Limits of Access
The philosophical version of this question is sometimes called the problem of other minds. I have direct access to my own experience but only inferential access to yours — I observe your behavior and your words and construct a model of what's happening inside you, but I never actually experience your experience. This gap is unbridgeable in principle. Even with perfect honesty and infinite time, I'm always working from the outside, reconstructing your inner life from the traces it leaves rather than perceiving it directly.
This sounds bleak stated baldly, but in practice we navigate it constantly and mostly successfully. The models we build of the people close to us become quite good — good enough to predict their reactions, anticipate their needs, and coordinate a shared life. We don't need direct access to another mind to be genuinely close to it. We need a model accurate enough to act on, and that we can build.
The Person Keeps Changing
Complicating the picture further is the fact that the target keeps moving. Even if you could perfectly know a person as they are today, they wouldn't be the same person in five years. People change — their values shift, their circumstances reshape them, their experiences accumulate into new dispositions. The model you built of your partner at thirty may be subtly wrong by the time they're forty, not because you knew them poorly but because they've become someone slightly different while you weren't updating.
This is, I think, the actual source of much long-relationship drift. Two people build accurate models of each other early on and then stop updating, each continuing to relate to a version of the other that has quietly become outdated. The person feels unseen not because their partner never knew them but because their partner knew a previous version and never revised. The knowing has to be continuous to stay accurate, and continuous knowing is a lot of work.
What Intimacy Actually Requires
Given all this, intimacy can't mean complete knowledge of another person — that's impossible. What it can mean is a sustained, good-faith effort to keep the model current, combined with a comfort with the parts that remain opaque. The healthiest close relationships seem to involve both a deep familiarity and a residual sense of mystery: you know this person profoundly and you're still occasionally surprised by them, and the surprise is welcome rather than threatening.
The couples who seem most alive to each other after decades are often the ones who never fully closed the file on their partner — who kept asking questions, kept noticing changes, kept treating the other as a person still unfolding rather than a puzzle already solved. The ones who struggle are often the ones who decided years ago that they had their partner figured out and stopped paying attention. Certainty about another person, paradoxically, is often the thing that ends the real knowing.
Self-Knowledge Comes First
There's a complication we usually skip: we can't fully know another person, but we can't fully know ourselves either. Much of our own inner life runs below conscious awareness — motives we don't recognize, patterns we can't see, feelings we misidentify. If the model I have of myself is incomplete and sometimes wrong, then the model I offer to others is built on shaky ground to begin with. Two people trying to know each other are each working from imperfect self-knowledge as their starting material.
This cuts in an unexpectedly hopeful direction, though. If knowing another person is limited partly by their limited self-knowledge, then sometimes a close friend or partner can see things about you that you can't see about yourself — patterns visible from the outside that are invisible from within. The people closest to us occasionally know parts of us better than we know them ourselves. Complete mutual knowledge is impossible, but this cross-illumination, each person seeing what the other can't see in themselves, is one of the genuine gifts of intimacy, and it partly compensates for the access we can never have.
What I Keep Coming Back To
We can't truly know another person in the sense of complete access — that door is closed by the basic structure of consciousness. But we can know them well enough, provisionally and continuously, to build something real together. The trick is to hold the model loosely, keep updating it, and stay curious about the parts that remain out of reach. The mystery isn't a failure of intimacy. Handled well, it's part of what keeps intimacy alive.
In the end, the impossibility of complete knowledge is not a reason for despair but a reason for continued curiosity. The people we love remain partly unknowable, and that residual mystery, rather than being a failure, is part of what keeps long relationships alive. The moment you decide you have someone completely figured out is usually the moment you stop actually seeing them.