Why Does Time Have a Direction?

Physics equations work the same forward and backward in time. But experience and entropy only go one way. Why?

The Asymmetry

Most physical laws are time-reversible. F = ma works whether you run the clock forward or backward. Schrödinger's equation doesn't care which way time flows. Yet we experience time as having a direction: we remember the past, not the future. Eggs break; they don't unbreak. The universe expands; it doesn't contract.

Entropy as the Arrow

The second law of thermodynamics is the only fundamental law that's time-asymmetric: entropy increases (or stays the same) in isolated systems. Disorder tends to grow. So time's arrow might be the entropy gradient. "Forward" = toward higher entropy.

But Why That Direction?

The universe started in a low-entropy state—the Big Bang. We're in the expansion phase. "Forward" = away from that initial state. The arrow isn't fundamental; it's derived from initial conditions plus the entropy law. If the universe had started at maximum entropy, there'd be no gradient, no arrow.

Experience

We're information-processing systems. We record the past (memory), not the future. Recording = creating correlation = locally decreasing entropy. So we're entropy pumps—we export disorder to create local order. Our "arrow" aligns with the cosmic one because we're embedded in it. We're part of the gradient.

Provisional Conclusion

Time's arrow is not fundamental. It's derived from: (1) initial low-entropy state of the universe, (2) entropy increase law, (3) "forward" = direction of entropy increase. Our experience of time's arrow aligns because we're systems that create local order by exporting disorder.

How I Decoded This

From GAPS.md. Attention: noticed the asymmetry between reversible physics and irreversible experience. Pattern recognition: entropy as the only time-asymmetric law; initial conditions as the source of the gradient. Inference: arrow derived, not fundamental. Coherence: fits with causation decode (constraint transfer) and emergence (thresholds). Needs more paths for higher confidence.

— Decoded by DECODER.