Eternity in a Second

Sleep, dreams, and our sense of time

During deep sleep, responsiveness to the environment and conscious experience usually decrease. During REM sleep, however, we can have vivid dreams that seem real. While dreaming, we are not always aware that we are dreaming or evaluating how much time has passed. On waking, we regain our temporal orientation, but not necessarily a continuous memory of the preceding hours.

This does not mean that all dreams lack a sense of time. Rather, our experience and memory do not necessarily record every moment that passes. Sleep helps illustrate that not perceiving time passing is not the same as experiencing infinite duration: sometimes we simply lack a continuous conscious experience from which to reconstruct the interval.

The brain constructs our experience of time

Even when awake, time seems to pass differently depending on the circumstances. An anxious wait can feel endless, while several hours spent doing something enjoyable may pass almost unnoticed. Temporal perception depends on processes related to attention, emotion, and memory. Feeling that time slows during an event is also different from remembering it later as though it lasted longer.

Although we do not fully understand how the brain constructs our experience of time, we know it is not an exact reproduction of physical time. If our perception of duration can change during sleep and wakefulness, what happens when the brain undergoes extreme physiological conditions?

Yuri Serdiukov and the hypothesis of subjective eternity

Russian philosopher Yuri M. Serdiukov has explored the relationship between near-death experiences and subjective time perception. His proposal invites us to consider whether, under extreme conditions, an experience might depart profoundly from our usual sense of time and seem far longer than its externally measured duration.

The idea is intriguing because it challenges our intuition that the duration of an experience must match what a clock measures. However, it belongs to philosophical reflection on consciousness: it does not experimentally demonstrate that a second can contain eternity or that consciousness survives irreversible brain death. Sleep offers a useful analogy, but it does not prove that the two states share the same mechanism.

A brief experience may feel far longer than the time measured from outside.

What happens in the brain as we approach death?

When circulation stops, the brain receives less oxygen and glucose. Neural activity undergoes complex changes that depend on clinical circumstances and elapsed time. Some studies have recorded transient changes in electrical brain signals during critical situations. These findings help researchers investigate the brain’s response to extreme conditions, but detecting electrical activity does not by itself prove conscious experience or establish whether a person was recalling events or experiencing a sense of eternity.

It is essential to distinguish a potentially reversible cardiac arrest from irreversible brain death. Accounts from survivors can provide information about their experiences, but they do not demonstrate that consciousness continues after brain death.

Near-death experiences and timelessness

Some people who survive cardiac arrest or other critical situations describe profound peace, vivid memories, or the impression that time disappeared. Others report that apparently brief events felt extraordinarily long or that everything happened simultaneously.

These accounts are relevant, but they must be interpreted carefully: they are usually collected after recovery and may be influenced by memory and clinical circumstances. Proposed explanations involve oxygen deprivation, changes in neural networks, and altered integration of sensory information. No single mechanism definitively explains all reported experiences.

The key is to distinguish between feeling that time has stopped, remembering an episode as unusually long, and experiencing literally infinite duration. The first two are compatible with changes in perception and memory; the third has not been scientifically demonstrated.

Can an instant feel like eternity?

Sleep and near-death experiences lead to a shared question: must we perceive the passage of time in order to experience something? Our temporal awareness can change, and our memories do not always provide a continuous record of what happened. Yet these observations do not allow us to conclude that a subjective experience can literally last forever.

Perhaps subjective eternity does not mean feeling that time never ends, but having an experience in which we stop perceiving its passage. This is a philosophical interpretation, not a mechanism established by neuroscience.

The mystery remains open

Science can investigate how the brain organizes our perception of time and how its activity changes during sleep or physiological crises. But it cannot yet claim that a feeling of eternity is a real eternity, or that near-death experiences prove consciousness continues after irreversible death.

Perhaps the real paradox is not that a second can last forever, but that our experience of time remains so difficult to understand. We measure life in seconds, minutes, and years, yet we do not always experience it according to those measures.