Turns out the math for how things cool down or rot works just fine even if time doesn't move forward.
arXiv · March 17, 2026 · 2603.13738
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The Takeaway
For decades, physicists assumed that the math used to model heat flow and quantum decay only worked in one direction. This paper proves the formulas are actually time-symmetric, suggesting that the 'arrow of time' is a human-made convention rather than a fundamental law of physics.
From the abstract
The Markov approximation is arguably the most ubiquitous tool in physics, underpinning quantum master equations, stochastic processes, and -- via Shannon's channel model and Lamport's logical clocks -- the foundational assumptions of distributed computing. It is widely assumed that Markovianity inherently implies temporal asymmetry: that the Markov property is a forward-in-time-only (FITO) construct. We show that this assumption is a category mistake in the sense of Ryle (1949).Guff, Shastry, an