In the grand orchestra of the universe, every instrument has its own rhythm. Electrons in an atom make quantum leaps in femtoseconds, neurons in the brain exchange signals in milliseconds, and a human needs tenths of a second to become aware of the 'now.' Physicists have long sought the conductor who brings these disparate parts together into a single melody of directed time.
One hypothesis is the Growing Block Universe. In it, spacetime is not a frozen crystal but rather a coral that accretes new layers. Growth occurs along special lines linked to the irreversibility of quantum processes. It is this continuous expansion that sets the arrow of time — from past to future. The brain, as part of this growing structure, attunes to the overall rhythm, and thus 'brain time' emerges.
But here a soloist appears who does not follow the common score. This is our personal experience of time — what philosopher Henri Bergson called 'duration.' Duration is not merely a sequence of moments but their qualitative, indivisible flow. The authors of the work argue that even if we build a bridge from quantum to neurons, we cannot throw a bridge from neurons to the very feeling of 'I am now.' The gap between physical time and lived time is not physical but cognitive. This does not mean science is powerless. It means that the melody of being has a score that cannot be written in notes: it can only be lived.
The shortest time interval a human can consciously perceive is about 30–40 milliseconds. Anything shorter merges into a continuous 'now' for us, even though physically the events are already separated.