Curvature and Free will (part 1)

[_The Nehor]

I don't see how lacking one solid present is a problem for free-will. I have a present existence in which I experience space-time and can interact with it as I will. How does fogginess in how others experience time relative to me have any impact on my exercise of free will?

[_Tarski]

I don't see how lacking one solid present is a problem for free-will. I have a present existence in which I experience space-time and can interact with it as I will. How does fogginess in how others experience time relative to me have any impact on my exercise of free will?

It's not fogginess that is the problem, it is definiteness. If you can accept the idea that all of your future sins are set in stone and still feel free then fine.
For many people, the sense of freedom depends on the notion that the future is not a definitive actuality in the way that the past is a definitive actuality.

[_cksalmon]

It's not fogginess that is the problem, it is definiteness. If you can accept the idea that all of your future sins are set in stone and still feel free then fine.
For many people, the sense of freedom depends on the notion that the future is not a definitive actuality in the way that the past is a definitive actuality.

From some of your comments, I take it that, for you, a compatibilist framework--of whatever stripe, secular or religious--is ultimately less than compelling as a ground for what we might term "genuine" libertarian freedom. Am I reading you correctly, at this point?

It's a halfway house, to be sure.

[_Tarski]

It's not fogginess that is the problem, it is definiteness. If you can accept the idea that all of your future sins are set in stone and still feel free then fine.
For many people, the sense of freedom depends on the notion that the future is not a definitive actuality in the way that the past is a definitive actuality.

From some of your comments, I take it that, for you, a compatibility framework--of whatever stripe, secular or religious--is ultimately less than compelling as a ground for what we might term "genuine" libertarian freedom. Am I reading you correctly, at this point?

It's a halfway house, to be sure.

A compatibility framework like Dennett's in "Freedom Evolves" is probably about all that current physics allows (barring some yet hidden metaphysics of consciousness tracing it's way through a charmed branches in a many worlds interpretation of QM or some other such metaphysically extravagant approach). I am pretty much OK with a compatibility framework, but there is a residual dissatisfaction.

[_asbestosman]

Alright smarty doctor x 1.5 (the half is an honorary 1/2 doctorate degree from my own blunder ;-) ):

Since time is relative, who's frame of reference are we using when we say that the universe is X billion years old? Do all frames of reference / world lines give the same answer for how long ago?

When we speak of the universe expanding spatially, is that always relative to an observer's frame, or is there some notion of an absolute or universal frame of reference (I would have thought not). Furthermore, since time and spatial dimensions are joined together, does that mean the universe's time is expanding? Also, why do we have an arrow of time--why don't have people with world lines progressing backwards or sideways relative to ours.


Finally, do you perceive any theological problems for LDS regarding this? It seems to me that one might still be held accountable for natural consequences to his actions even if there are no absolute notions of past and present. One thing that did seem interesting to me though is the question of reserrection. Since the order of reserrection will be based on faithfulness, it appears that relativity may make a loophole where a telestial sinner could rise before a celestial saint. I wonder who's frame determines resurrection order. Also, what happens if someone's body (or spirit) falls into a black hole? When are they resurrected?

[_Tarski]

Alright smarty doctor x 1.5 (the half is an honorary 1/2 doctorate degree from my own blunder ;-) ):

Since time is relative, who's frame of reference are we using when we say that the universe is X billion years old? Do all frames of reference / world lines give the same answer for how long ago?

When we speak of the universe expanding spatially, is that always relative to an observer's frame, or is there some notion of an absolute or universal frame of reference (I would have thought not).

Curvature makes the difference here. Depending on the model used, various foliations and time parameters suggest themselves but we are no longer speaking of inertial frames but rather just natural or "onvious" frames. Here is a link to a discussion of this issue. But not that the first poster should have perhaps said constant mean curvature instead of totally geodesic.

http://www.physicsforums.com/archive/in ... 41686.html

Furthermore, since time and spatial dimensions are joined together, does that mean the universe's time is expanding?

LOL, well I would say yes and no depending on how one interprets the question. One thing is for sure, if one uses one of the usual spacetimes, it is the leaves of the prefered foliation that gets "bigger" as one moves forward in time from one leaf to the next. So in this sense it is space that gets bigger. But you are right to expect a more subtle answer since space and time are now joined in a certain way. But note that the field of light cones still pick out a certain sense of a timelike direction as opposed to a spacelike direction. Any vector inside the light cone is timelike.

Also, why do we have an arrow of time--why don't have people with world lines progressing backwards or sideways relative to ours.

This is indeed a serious question and pages could be written about it. Are you refering to the thermodynamic arrow of time or are you asking why some observers aren't moving backwards in time (so to speak) or why no observers are traveling in spacelike directions (sideways)? (The latter would be equivalent to moving faster than light).

Finally, do you perceive any theological problems for LDS regarding this? It seems to me that one might still be held accountable for natural consequences to his actions even if there are no absolute notions of past and present.

Well, the argument is that we lose the ability to say that the future is less definite than the past since different observers disagree about which events are in the past and which are in the future. This might seem to threaten notions of free will. One objection that eventually doesn't work well is to point out that all observers agree about which events lie in the absolute future of a given event. But. Lockwood has an argument to the effect that this doesn't really help the problem.

[_asbestosman]

This is indeed a serious question and pages could be written about it. Are you refering to the thermodynamic arrow of time or are you asking why some observers aren't moving backwards in time (so to speak) or why no observers are traveling in spacelike directions (sideways)? (The latter would be equivalent to moving faster than light).

Both are interesting, but I especially had the latter in mind. I understand how the Lorentz transform prevents massive objects like you and me from suddenly accelerating to the pont where our world lines are backwards or sideways from each other. I just wonder why there can't be other objects that actually do travel faster than light and actually do move backwards compared to us. Or maybe there are such objects. I think it'd be fascinating if there were some kind of aliens that we could meet where we move backwards relative to them and vice-versa.

I also wonder if the thermodynamic arrow of time would make such a meeting impossible since some observers would have the apparent change in entropy flow in different directions.