Why Time Travellers Might Return Empty-Minded

Time travel is possible. However, there is one condition: you cannot remember anything from the time travel. This unsettling scenario arises from the work of mathematician Lorenzo Gavassino, who examined what the laws of physics, especially the second law of thermodynamics, imply for time travellers. The law states that entropy(disorder in a system) always increases. But in time travel, where a traveller follows a closed loop back to the starting point, entropy must return to its original value.

This is where the paradox comes in. To meet both conditions, entropy must rise to a maximum before decreasing. When entropy reverses, all processes tied to it, including ageing, molecular motion, and even memory formation, must also reverse. As Gavassino shows mathematically, memories gained during the journey would inevitably be erased when the system resets to its starting state. Clocks, too, would fail, ticking inconsistently along a closed timelike curve.

Yet this theory leaves a glimmer of hope. Perhaps entropy rules apply only to systems as a whole, not to every part. If so, some subsystems, like human memory, might preserve information even while total entropy follows the cosmic rulebook.

To conclude, Gavassino’s findings transform time travel from a fictional adventure into a puzzle of physics, memory, and causality. Even if a time machine existed, travellers might return with no story to tell, because they would have forgotten it all.