On the Reversibility of Physical Law
On the Reversibility of Physical Law
This work is about small, simple ideas with radical consequences. The originating problem of this series is that all classical laws of physics operate the same with time running forward as with time running backward. This is called time-reversible symmetry. That time has a direction, flowing from the past through the present to the future is something we take for granted, but our best physical models don’t privilege this direction of flow. Wrestling with this apparent paradox guides us to unexpected, illuminating ideas about the nature of our world.
Four ideas demonstrated here lead to the conclusion that there is no arrow of time in the physical laws governing small-scale interaction, but rather that, through entropy, a direction emerges at the larger scale.
The first piece, Spacelike Time, demonstrates the idea that laws of physics are time-reversible symmetric and that time is a dimension akin to the spatial dimensions. Next, Configurations in Infinite Time introduces the idea of entropy. Waves warns us against assuming our intuitions are a reasonable guide and suggests that meaningfully different, even unexpected behaviors can be emergent at a higher level from the reality of the underlying phenomena at a lower level. Finally, Space of States, Boundary Condition starts with time-reversible symmetric laws and shows that from a boundary condition of low entropy, through the action of these laws, higher entropy emergence and with it the arrow of time that we experience.
1. Spacelike Time: Candle #153 – 8 hours 17 minutes 11 seconds in 5.5 meters
2. Configurations in Infinite Time (Or 光継ぎ?)
3. Waves #4: Action dissolving into time resolution dependence
4. Space of States, Boundary Condition
Thematic Variations
