Time might be the process of turning unknowns into records
In short: In quantum mechanics, time is perfectly symmetrical; equations work just as well moving backward as forward. Yet our world moves in one direction. The answer may lie not in physics alone, but in the way information accumulates as the universe transforms uncertain possibilities into a definite past.
To understand why time has an 'arrow,' physicists look toward entropy—the measure of disorder within a system. In thermodynamics, systems naturally move from ordered states to disordered ones, such as two gases mixing in a chamber. While it is statistically improbable for those gases to unmix themselves, the process is physically possible. This creates a tension: if time were strictly tied to entropy, reversing entropy (like cooling a refrigerator) should reverse time, but it does not.
A more nuanced perspective suggests that time is specifically the process of bringing an unknown future into a recorded past via the present. Every passing moment represents a transition where indeterminate quantum events—which exist only as probabilities—become classical, definite facts. This transition creates new information about the universe. Because entropy is directly tied to the amount of information required to describe a system, the constant 'churning' of the present into a fixed past ensures that entropy and information always increase.
This theory, championed by physicist Lee Smolin and expanded upon as a conjecture, suggests that the arrow of time is defined by knowability. The past is what has happened; the future is what hasn't. This leads to a profound cosmological mystery: if entropy only increases, the universe must have started in a state of extremely low entropy near the Big Bang. If the universe eventually reaches a state where no new information can be recorded—no movement, chemistry, or thought—it remains an open question whether time would continue to flow at all.
Ultimately, this framework shifts our view of time from a fundamental container of existence to a byproduct of information dynamics. It suggests that we perceive the forward flow of time because we are living in the constant conversion of 'not yet' into 'already was.'
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- Summary by Intellect · source: Nobody Knows What TIME Really Is. But it might be this...
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