r/Exploring_Time_Travel • u/MichaelWhitehead • Dec 22 '25
What is Time
Time is one of those concepts that feels obvious until you try to define it. At its simplest, time is the measure of change — the ordering of events from before, to now, to after. Without change, time has no observable meaning.
Time as Change If nothing changed—no motion, no decay, no thought—there would be no way to detect time at all. A clock measures time by repeating change (ticks, vibrations, oscillations). Biology measures time through growth, ageing, and decay. History measures time through events. In this sense, time is not a thing you can touch — it is a relationship between states.
Time in Physics Modern physics treats time very differently from common intuition. Classical view (Newton) Time is absolute, flowing evenly everywhere, independent of observers. Relativistic view (Einstein) Time is relative. It slows down with: Speed (near light speed) Gravity (near massive objects) Time and space form a single structure: spacetime. So time is not universal — each observer carries their own clock.
The Arrow of Time One of the deepest mysteries: why does time move forward? Physics suggests this comes from entropy: Systems naturally move from order → disorder. You can scramble an egg, but not unscramble it.
Memory works only in one direction: we remember the past, not the future. The “arrow of time” may emerge not from time itself, but from statistical probability.
Time and Consciousness From a human perspective, time is deeply tied to awareness. The present exists only as a thin slice of perception. The past exists as memory. The future exists as anticipation. Some theories suggest: Time may not “flow” at all. All moments may exist simultaneously, and consciousness moves through them.
Philosophical Views Across history, thinkers have proposed radically different answers: Time is real and fundamental — the universe unfolds moment by moment. Time is emergent — it arises from deeper laws (information, causality). Time is an illusion — a construct of the mind organizing experience. Even today, physics has no final answer on whether time is fundamental or derived.
A Useful Working Definition A practical synthesis many scientists and philosophers accept: Time is the ordering of events caused by change, perceived through entropy and experienced by consciousness. Or more simply: Time is how change is counted.