More than two thousand years before the word liminality entered academic language, Plato was already fascinated by life at the threshold. In his famous Allegory of the Cave, prisoners spend their entire lives chained inside a cave, believing the shadows cast on the wall before them to be reality itself. When one prisoner escapes into the daylight, he gradually realises that the world is far richer than he had ever imagined. In that moment, he stands between ignorance as the prisoner and understanding in the freedom of his newly discovered world. Between certainty and uncertainty, between the familiar and the unknown. The story is not simply about discovering truth, but about the unsettling transition between one way of knowing the world and another. It is one of philosophy's earliest explorations of what we would now recognise as a liminal state.
The term liminality, introduced much later by anthropologist Arnold van Gennep and developed by Victor Turner, describes a threshold between one state and another. Traditionally associated with rites of passage, liminality refers to periods in which familiar structures dissolve before new ones emerge. Yet liminality need not be confined to social rituals. It may also describe a fundamental property of the mind itself.
Perhaps nowhere is this more intriguing than in perception. We often think of perception as a direct window onto reality and imagination as something entirely separate: an internally generated world of our own making. But philosophy has long questioned whether this distinction is so clear.
René Descartes famously sought certainty in the midst of radical doubt. If the senses could deceive us, and if dreams could masquerade as reality, what could possibly remain certain? His answer became one of the most influential statements in philosophy: Cogito, ergo sum—I think, therefore I am. The act of thinking proved, at the very least, that a thinking self existed.
But perhaps the cogito can be read differently. Rather than proving that consciousness is something fixed, could thinking instead reveal consciousness as something continually unfolding? Not I think, therefore I am, but I think, therefore I become.
This shift echoes the phenomenology of Maurice Merleau-Ponty, who argued that perception is not a passive recording of sensory information but an active engagement with the world. We do not simply receive reality; we participate in its construction through our embodied interactions. Perception is therefore never static. It is always in motion, continually negotiating between what is sensed, what is anticipated, and what is possible.
Shakespeare captured this beautifully in Macbeth. Standing on the threshold of murder, Macbeth asks:
"Is this a dagger which I see before me,
The handle toward my hand?"
Moments later, he questions whether it is "a dagger of the mind, a false creation." The audience is left suspended in uncertainty. Is the dagger real? Is it imagined? Or is it something occupying the threshold between perception and imagination? Macbeth himself cannot tell. His consciousness has entered a liminal state in which prediction, desire, fear, and sensory experience become almost impossible to separate.
Modern audiences encounter a similar question in The Matrix. How can we know that what we perceive corresponds to reality? While framed as science fiction, the film revisits one of philosophy's oldest problems: whether consciousness experiences the world directly or constructs it from within.
Remarkably, contemporary neuroscience is beginning to converge on these philosophical insights. Rather than passively receiving sensory information, the brain continuously generates predictions about the world before sensory evidence arrives. Internal forward models anticipate the consequences of our actions, allowing us to move smoothly, recognise familiar events, and rapidly update our understanding when predictions fail. In many respects, the brain is always imagining what is about to happen next.
It is likely that imagination itself emerges from these predictive mechanisms. The same internal models that allow us to anticipate future events may also allow us to simulate actions, rehearse possibilities, and construct experiences that are not immediately present. Imagination, from this perspective, is not detached from perception but grows from the very machinery that makes perception possible.
This brings us back to liminality. If perception is shaped by prediction, and imagination is an intentional extension of those same predictive processes, then consciousness itself may exist at the threshold between them. It is neither purely sensory nor purely imagined, but a continuous negotiation between the external world and internally generated possibilities.
Which leaves us with a question rather than a conclusion.
Perhaps consciousness is not best understood as a thing we possess, but as a process we inhabit: a liminal state, continually balancing sensation and simulation, reality and possibility, perception and imagination.
If so, Descartes' famous declaration may invite a new interpretation.
I think, therefore I become.