# Time: The First Quantum Concept ## The Paradox of Time * Is "now" a single static moment that is "swept" through time. Or does each moment, from its *own intrinsic perspective*, have its own "now"? * In the example deutsch works through, the arrow can be thought of as a sequence of snap shots * Similarly, we know that "now" is a sequence of snap shots. But 11.2 does not make "now" a sequence of snap shots. It is a single snap shot! * So deutsch highlights this is a contradiction. * A "thing" does not change. For instance, an object at a specific snapshot in time does not exhibit change! For a snapshot is inherently static. *Change* is a sequence of snapshots. In other words, change is a sequence of unchanging things. * Big ideas floating around here * intrinsic vs extrinsic observer * static, change, unchanging * perspective * 2-d image trying to encode too much information * think about what the arrow encodes * How do [Spacetime](Spacetime.md), [General Relativity](General%20Relativity.md) and [Special Relativity](Special%20Relativity.md) fit in here? It seems that * Spacetime is incompatible with the existence of cause and effect (pg 274) * Ambiguity of counterfactuals (pg 275) * Imagine trying to kill faraday - there is no way of reducing the ambiguity around that statement and what would happen after * For instance, say he dies via the plague. Would that slow tech progress? Presumably, but it could increase it for it could lead thousands of people to take up science to try and solve the problem * Now say he dies via a rare isolated virus that impacts literally no one else. Even then, we don't know what would happen next. His death could have opened the doors for a set of bright young scientists that would have attacked these problems with more vigor * Either way, the laws of physics are the same, and yield a single, static spacetime (block universe) * We need to introduce the multiverse in order to solve this >Other times are just special cases of other universes. What do I mean by this? Consider the snapshots of space that make up spacetime. In order to construct the full, 4d spacetime, we simply need two things: one single snapshot and the laws of physics. Given a single snapshot and the laws of physics, we can then determine what the prior and subsequent snapshot must have been. Then we can "glue" them together. Now we have 3 snapshots, glued together. We can then continue doing this indefinitely. But now consider this in the case of the multiverse. Imagine we now slice the multiverse into a heap of individual snapshots (not super-snapshots, just a bunch of snap shots). What can we then glue them back together with? Again, our only valid options are the intrinsic, physical properties of the snap shots and the laws of physics. If time in the multiverse were a sequence of moments, it would have to be possible to take all snapshots at a given moment and construct a super snap shot. There is no way of doing that. In the multiverse, snapshots do not have "timestamps"! (TODO: make sure you understand why this is the case). There is no such thing as which snapshot from another universe happens ‘at the same moment’ as a particular snapshot in our universe, for that would again imply that there is an overarching framework of time, outside the multiverse, relative to which events within the multiverse happen. There is no such framework. (TODO: need to elaborate on this - not fully clear why gluing doesn't work here, or why there is no such thing as single moment. In my mind, I have a picture of traditional spacetime being constructed vertically. Given a single snapshot and the laws, we can indefinitely construct the vertical stack of snap shots. Now when we introduce the multiverse, we have spacetimes extending horizontally. Why can't we use the laws of physics and a single snapshot to construct a super snapshot, moving out horizontally?) Include * [Common Sense Theory of Time](Common%20Sense%20Theory%20of%20Time.md) --- Date: 20241201 Links to: Tags: References: * []()