When we say something is “mine,” we are doing something profound. We are not just stating a legal fact. We are expressing a relationship between ourselves and the world around us. This experience of “mine-ness” has fascinated philosophers for centuries because it reveals something essential about what it means to be human. Two thinkers in particular - the German philosopher Martin Heidegger and the Polish philosopher Leon Litwinski - offer us powerful ways to understand this everyday experience. Their ideas help explain why losing a favourite mug can feel like losing part of yourself, or why another person using your things without permission can feel like a small violation.

Let us begin with Martin Heidegger, who in his 1927 work Being and Time introduced a concept that translates roughly as “mine-ness.” The German word is Jemeinigkeit, which literally means “in each case mine-ness.” Heidegger uses this term to describe something fundamental: for each of us, existence is always personal. My life is not a generic life. It is my life, and I must live it. My death is not an abstract event that happens to people; it is something that will happen to me, and me alone. My possibilities are my own, my choices are my own, and my responsibilities are my own.

Heidegger writes: “Dasein is an entity which is in each case mine.” By “Dasein,” he means the kind of being that we humans are – the being that understands its own existence. When he says Dasein is “in each case mine,” he is pointing out that you cannot separate your existence from the fact that it is yours. You cannot step outside your own life and view it from a neutral perspective. It is always experienced from the inside, always as “mine.” This is not a choice you make; it is simply the structure of being human.

Think about it. When you wake up in the morning, you do not experience a generic consciousness waking up. You experience your consciousness. Your headache is not just a headache; it is your headache. Your memories are not floating around in some collective pool; they are your memories. Even when you try to escape yourself through distraction, entertainment, or even self-destructive behaviour it is still you doing the escaping. The “mine-ness” of your existence is inescapable.

This becomes most obvious when we consider death. Heidegger argues that death is “the possibility of the impossibility of any existence at all.” It is the one thing that nobody can do for you. Other people can pay your taxes, answer your emails, or even live your life in some superficial ways, but nobody can die your death for you. The absolute “mine-ness” of death reveals the “mine-ness” of existence itself.

But Heidegger’s concept of “mine-ness” extends beyond just existence. It shapes how we relate to everything in our world. The world appears to us not as a neutral collection of objects, but as a world of possibilities and concerns that matter to me. The desk is not just a wooden structure; it is where I work. The street is not just asphalt; it is the route I take to visit my friend. The entire world is soaked in this quality of “mine-ness.”

Now let us turn to Leon Litwinski, a Polish philosopher who wrote about the phenomenology of possession in the early twentieth century. While Heidegger was concerned with the “mine-ness” of existence itself, Litwinski examined how we experience things as ours in a more everyday sense. His work The Philosophy of Property explores what happens psychologically when something becomes “mine.”

Litwinski argues that possession is not just a legal relationship between a person and an object. It is a psychological and existential relationship. He writes: “Possession is a specific relation of a person to a thing, consisting in the fact that the thing is incorporated into the personality of the possessor.” This is a dense statement, but its meaning is simple and profound. When something becomes “mine,” it becomes part of me.

Think about your favourite jacket. When you first bought it, it was just another item of clothing. But after years of wearing it, it has shaped itself to your body. The elbows are worn in exactly the places where your arms bend. The pockets have moulded to the shape of your hands. It smells like you. When you put it on, you do not have to think about it; it feels like a second skin. In Litwinski’s terms, the jacket has been “incorporated into your personality.” It has become an extension of yourself. If someone were to borrow it without asking, you might feel not just annoyed but slightly violated. This is because they are not just using an object; they are handling something that has become part of your extended self.

Litwinski identifies three dimensions of this incorporation. First, there is the physical dimension. We manipulate objects, wear them down with our bodies, leave our marks on them. A gardener’s spade becomes curved from the pressure of their foot. A musician’s instrument develops wear patterns from their fingers. These physical changes are like a signature, a record of the person’s presence.

Second, there is the psychological dimension. We invest objects with our emotions, memories, and identity. A photograph is not just paper and ink; it is a captured moment of joy. A childhood toy is not just plastic; it is a vessel for nostalgia. A wedding ring is not just metal; it is a symbol of commitment. The object becomes a storehouse for our inner life.

Third, there is the social dimension. Possessions signal to others who we are. A bookshelf full of philosophy texts says something about its owner. A garden full of roses says something about the gardener. A car kept in immaculate condition says something about the driver. These objects become part of how we present ourselves to the world and how the world recognises us.

The fascinating thing is that this process of incorporation can happen with almost anything, not just objects we legally own. Consider the desk you use at work. Legally, it belongs to your employer. But if you have worked there for ten years, arranged your pens in a particular order, stuck your childrens’ drawings to the monitor, and worn a smooth patch on the wood where your wrist rests, it has become “yours” in Litwinski’s sense. When the company announces a move to hot-desking, you might feel real grief. This is not mere sentimentality. It is the pain of separation from something that has become part of your extended self.

We can see the difference between Heidegger and Litwinski clearly here. Heidegger’s “mine-ness” is ontological – it concerns the very nature of existence itself. It is the unavoidable fact that your life is yours and nobody else’s. Litwinski’s “mine-ness” is phenomenological – it concerns how we experience and relate to the world. It describes the process by which objects become incorporated into our sense of self. Yet the two concepts overlap and support each other. The fundamental “mine-ness” of our existence, described by Heidegger, is what makes Litwinski’s process of incorporation possible. Because we experience the world as “mine,” we can make parts of it truly ours.

Let us consider some more everyday examples to make this concrete.

Your smartphone is an obvious case. Physically, it bears the scratches of your pockets, the smudges of your fingers, the specific arrangement of apps on the screen. Psychologically, it holds your photos, your messages, your notes, your browsing history – a digital extension of your memory and personality. Socially, it is the tool through which you maintain your relationships, your presence in social networks. If you were forced to switch to a generic, brand-new phone, you would feel disoriented, even if the new phone were technically superior. The old phone has become part of you.

Consider also your home. A house becomes a home through this process of incorporation. You paint the walls colours you like. You arrange furniture to suit your habits. You fill it with objects that matter to you. The creaky floorboard in the hallway, the window that sticks slightly, the way the light falls in the kitchen in the morning – these become part of your daily reality, part of the texture of your life. A home is not just a shelter; it is an external manifestation of your inner world. This is why moving house can be so traumatic. You are not just changing address; you are extracting yourself from a space that has become part of your identity.

Even abstract things can become “mine” in this way. Your job, when you have done it for years, becomes part of you. The particular way you organise your inbox, the relationships you have built with colleagues, the expertise you have developed – these are incorporated into your personality. Retirement, or losing that job, can feel like losing part of yourself. Similarly, a role you play in your family – the organiser, the peacemaker, the joker – can become so incorporated that you hardly know who you are without it.

The reverse is also true. Sometimes we experience things as “mine” that we would rather not. A chronic illness can become incorporated into your personality, shaping your daily routines, your sense of possibility, how others see you. You might say “my arthritis is acting up today,” and that “my” is significant. The illness has become part of your extended self, whether you want it or not. Traumatic memories can work the same way, forcing themselves into your sense of who you are.

Understanding the phenomenology of “mine-ness” helps explain many of our emotional reactions. Why are we so attached to objects with little monetary value? Because they have become part of us. Why do we feel violated by theft or vandalism, even when insured? Because it is not just property that is taken; it is part of our extended self. Why do we find it so difficult to declutter? Because we are not just throwing away objects; we are pruning parts of ourselves.

It also explains why minimalism, while appealing in theory, can be so difficult in practice. The minimalist ideal suggests we should own only what we truly need. But “need” is not just about utility. We need objects that have become part of us, that support our sense of identity and continuity. A perfectly functional, minimalist apartment can feel sterile and alienating because it has no history of incorporation. It is nobody’s, and therefore it is hard for anybody to feel at home there.

This understanding also casts light on contemporary debates about digital ownership, privacy, and the “gig economy.” When our photos, our writings, our friendships exist on servers owned by corporations, what does “mine” mean? When we are forbidden from customising our workspace, or when we move to a new rental every year, what happens to the process of incorporation? These are not just economic questions; they are questions about how we maintain a coherent sense of self in a world that makes “mine-ness” increasingly precarious.

Heidegger and Litwinski, writing nearly a century ago, give us the tools to think about these modern problems. Heidegger reminds us that the deepest “mine-ness” cannot be taken away. However much the world changes, your existence remains yours. You cannot outsource your choices, your relationships, or your death. Litwinski reminds us that this fundamental “mine-ness” needs to express itself in the material world. We need to incorporate objects, spaces, and activities into our personalities to become fully ourselves. We are not ghosts in machines; we are embodied beings who make the world ours through use, memory, and care.

The next time you feel a pang at the thought of replacing your worn-out shoes, or a quiet satisfaction in arranging your books on a shelf, or a strange emptiness in a pristine hotel room, pay attention. These feelings are not trivial. They are the phenomenology of “mine-ness” making itself known. They are the echo of Heidegger’s insistence that existence is always mine, and the whisper of Litwinski’s observation that we become ourselves by making things ours. In a world that often feels alienating and impersonal, these small acts of incorporation - these quiet declarations of “mine” - are how we build a life that feels like our own.