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Comment by tempodox | Hacker News Reader

Being used to live in a world of cause and effect, I'm having a really hard time of getting my head around “random fluctuations” that seem to have an effect but no cause. That's about as illogical to me as the idea of a magnetic monopole. But then,

> ...particles are merely bubbles of froth, kicked up by underlying fields. Photons, for example, are disturbances in electromagnetic fields.

I can get behind this, even if only by way of misunderstanding. All deviation from nonexistence (Void) is a disturbance. All existence is one giant software bug in the fabric of Nothingness (if it could have something like fabric).

That's why I've got to love Physics. To me, it's the most exquisite collection of brain-racking mysteries I can imagine (modulo the narrow bounds of my imagination, of course).

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> I'm having a really hard time of getting my head around “random fluctuations” that seem to have an effect but no cause

So you're saying God does not play dice with the universe? :)

Nope. Just Craps.

Perhaps “random fluctuations” are as much random as Brownian motion. I.e. there is cause and effect on a finer level (yet not possible to probe with current techniques), however a large number of interacting particles renders analytical prediction infinitely complex task.

Physics (as far as we know) doesn't care about the direction of time. Cause and effect depends on a fixed direction of time.

Physics does clearly "care" about the direction of time, because physics is a description of the physical universe. Dissipation, entropy, quantum measurement... etc. all have time as a key concept.

Math may not care (and it's true that most of the fundamental physics equations are often time reversible). But the universe (and any experiment to date) clearly shows that time has a direction and the equations work in that direction.

That's only one time end of the universe has a very low entropy. If you have an area with maximum entropy, there is no way to tell.

Physics does are about the direction of time: https://en.wikipedia.org/wiki/T-symmetry

https://en.wikipedia.org/wiki/CPT_symmetry

Charge, Parity, and Time Reversal Symmetry is a fundamental symmetry of physical laws under the simultaneous transformations of charge conjugation (C), parity transformation (P), and time reversal (T). CPT is the only combination of C, P and T that is observed to be an exact symmetry of nature at the fundamental level. The CPT theorem says that CPT symmetry holds for all physical phenomena, or more precisely, that any Lorentz invariant local quantum field theory with a Hermitian Hamiltonian must have CPT symmetry.

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