O.k Phil
How about great follower of Hume (quoted by you) Ludwig Wittgenstein's view of causality?
Do you agree with him?
"A necessity for one thing to happen because another has happened does not exist.
There is only logical necessity." (Tractatus Logico-philosophicus, 6.37) Harper Collins Publishers.
Dr. Gibbs,
"It will be an acausal universe in which space and time are emergent. With them will come locality and causality, also both emergent features of the theory."
Emergence is acausal?
James
A new scientific truth does not triumph by convincing its opponents and making them see the light, but rather because its opponents eventually die, and a new generation grows up that is familiar with it.
Max Planck quote:
http://en.wikiquote.org/wiki/Max_Planck
Better trandlation from the Germany:
An important scientific innovation rarely makes its way by gradually winning over and converting its opponents; it rarely happens that Saul becomes Paul. What does happen is that it opponents gradually die out and that the growing generation is familiarized with the idea from the beginning.
Dear Philip Gibbs,
I admire your mastery of most current fields of physics, and accept that you are extrapolating many current avenues of thought to their extreme consequences. To some degree this resembles climbing up the rope and then pulling the rope up after you, which might be consistent, but is probably not physical. The artificial structures, such as Lattice Gauge Theories, were built on the foundation of temporal causation, and now seem to wish to throw away this foundation, to end up dependent on their own progeny, which 'emerge' from your interpretation of these structures.
You note that "causality is never experienced directly" and one "can never prove it definitively." Do you claim that consistency can be experienced directly or proved definitively?
A final question I have is whether you hope, by throwing away temporal causality, to open things up to "free will" or simply hope to span the universe with a six inch net, declaring that nothing exists smaller than six inches?
It's an impressive essay -- good luck in the contest.
Edwin Eugene Klingman
I submitted an essay yesterday. I argue that locality and unitarity are relaxed. Unitarity is the time translation of a particle by a Hamiltonian H. Of course we also have interaction Hamiltonians as well, where we compute Greene functions and propagators. This tends to define often what is meant by causality in physics: a propagator within or tangent to a light cone. Without unitarity our standard notion of causality is lost.
Oh BTW, I have never had a tooth cavity in my life. I think genes play some role in that. My wife is far more fastidious about dental hygiene than I am, and we continually sink lots of money into her teeth
Spacetime must in some ways be emergent. The Planck length L_p = sqrt{Għ/c^3} is such that metric elements g(L, L) := 1is such that its variation δg(L, L) ~ δL/L becomes comparable to the classical definition of the metric as L --- > L_p. The meaning of a distinct light cone becomes lost near the string or further the Planck scale.
Cheers LC
Philip,
Having followed your work, leading up to the discovery of the Higgs, I certainly respect your knowledge of physics. I must say though, that I'm one of those cranks who think much of the last century has been a wild goose chase. Intuition is a slippery fellow and we never quite know when it slips in unnoticed. We perceive time as a sequence of events and physics, in all its mathematical precision, re-enforces this assumption by treating it as a measure of duration. Logically though, it is not that the present that moves from past to future, but the changing configuration of what is, that turns future into past. To wit, the earth doesn't travel/exist along some vector from yesterday to tomorrow, tomorrow becomes yesterday because the earth rotates. It is not theory, but observation. Duration only exists within the present, not external to it.
The cat is not both dead and alive, because it is the collapse of probability which yields actuality.
Time then is an effect of action, similar to temperature. One is rate of change, the other is level of activity. Affect one and you affect the other. Say by accelerating atomic structure close to the speed of light and its level of activity slows, thus its rate of change slows.
We could use ideal gas laws to correlate temperature to volume, much as we use C to correlate distance and duration, but we don't because we understand temperature is a measure of action. While temperature underlays much of our biological and environmental functions, time, the sequence of events, from narrative to causality, underlays our mental functions. Not only is it intuitive, it is the foundation of knowledge.
So now our greatest minds have spent the last century constructing a modern form of epicycles, conceptually similar to the original. Instead of the sun appearing to move, it is the present which appears to move.
Feel free to ignore the point. Just about everyone else does.
Poincare was actually bolder than Einstein, and rejected the aether beforehand. Poincare had the Lorentz group, spacetime, etc. The real reason that special relativity took off in 1908 is because that is when Minkowski's paper was widely circulated, not because of reluctance to accept Einstein's ideas. Minkowski spacetime became popular very rapidly.
Also, you do not convince me to abandon causality, but of course the purpose is to challenge our assumptions so you must expect people to disagree with your essay.
Dear Philip,
I could not follow many of the learned technical arguments you put forth concerning the very important concept of causality, but am impressed by your tracing its treatment historically in philosophy and physics.
In my own simple-minded way I am loath to let go of causality, both intuitively in general, and specifically within the structure of my Beautiful Universe Theory which describes a Universe operating locally and causally through a simple transfer of angular momentum in an ether lattice, like some 3D abacus. In my model both space and time are emergent. And so is the concept of quantum probability.
In such a model the sense of your statement that "If time is emergent causality can be emergent too" would become: "in a causal network, time is emergent".
with best wishes,
Vladimir
Your Wittgenstein quote is more in line with what I have been saying but I dont want to gte caught up in the way philosophers use particular words like "necessity". I have concentrated on temporal causality in my esay. i.e causality in time where a past cause is related to a future effect. There is also a kind of logical causality that is a seperate but related concept. It is closer to the idea of reductionism in physics but also appears in mathematics where they try to reduce everything to axioms. I think that ultimately this form of causality fails as well and logical consistency is a better concept. The essay by Ellis is more about that kind of causality if you are interested in it.
Yes I am prepared for some disagreement and relish the opportunity to debate it.
Poincare was an interesting case and is often misunderstood. People have quoted his writings pre-1905 in a way that make it look like he preempted Einstein. However, if you study his philosopjhical position of "conventionalism" more closely you find that this was not quite the case. He recognised that a preferred reference frame may not exist in nature but he thought that it was right to define one by some convention. It is a peculiar mid-way philiosophical position that is hard for us to appreciate with our hindsight. That is why it is often misunderstood.
In special relativity it seems like a pedantic distinction but his position on non-euclidean geometry was that if someone proposed a non-euclidean geometry for space it would make no sense because you could impose a Euclidean geometry by convention and it would be better because it was simpler. It is true that you can do that and locally GR can be reformulated as if spacetime is flat and gravity is like any other force, but we dont consider that simpler. Fruthermore it takes away the possibility to consider spacetimes with different topologies. I think Poincare would have ultimately seen the light because of that but he died before the implications of GR became clear.
Yes, emergence is acausal. I find it hard to give a more elaborate answer because I dont know if or how you see it as causal.
Edwin, good to hear from you.
When you go to pull the rope up you find that it was never there in the first place.
Consistency is not something you need to experience. It is just a principle you need to apply when trying to formulate a theory. According to Geodel it cannot be proved in mathematics but if you assume mathematical consistency you can prove that a physical theory is logically consistent. Consistency with experiment is not proved rigorously of course but checks can be improved and it is obviously a firm requirement.
As for "free will", I dont think it can be defined in an operational sense, same for conciousness. If you can describe a physical test for them that everyone would accept I will reconsider, but otherwise I think they are illusions of our psychology rather than physical concepts. I know that many people disagree and will immediately go to rate me low for saying this but I am still waiting for their operational definitions of free will and conciousness. Depending on what they think these should be I may or may not agree that these things exist. :)
I like Price's ideas about the arrow of time but I am not convinced that backward causation can resolve the measurement problem. Interesting idea though.
I look forward to seeing your essay Laswrence.
Vladimir, it is nice to see that you have entered the contest again, good luck.
Thanks Phil,
I'm not sure how you get up the rope that wasn't there to begin with, but I think I get your gist. I also agree that "Consistency with experiment is not proved rigorously of course but checks can be improved", which is pretty much what I meant by the net. This year six inches, next decade five inches, etc.
Operational tests of consciousness or free will seem very unlikely to me, since such tests are better suited to purely objective reality whereas these are almost purely subjective. So I suspect consciousness will be one of those things that gets talked about but will never be hardcore physics. But I doubt anyone is assigning low marks based on comments accompanying an essay.
Yes, nicely put. An interesting point of view which isn't well known about I imagine.
Phil,
From your essay, "There is no general consensus yet on how to replace space and time but there is a widespread view that the space-time manifold as we knew it in general relativity is no longer the accepted starting point. It is just an approximation to some other unknown mathematical structure."
Space-time has become a distorted abstraction precisely because it did not have a proper mathematical structure. We have possessed the necessary knowledge, mathematical for 2,000 years, and physical law for 200 years, to establish the mathematical structure for space (distance) and time (event duration).
Some sixty years ago, the final piece of knowledge came into our possession that allowed the integration of space-time into a well established mathematical structure. The mathematical process, which I refer to as the "Methodology", was published in the July/August 2011 IEEE Potentials, titled, "A methodology to define physical constants using mathematical constants".
Since Jan 2011, IEEE does not allow authors to post their IEEE published papers on their academic or personal websites. A post-print is available at:
The concept in the Methodology is not taught in text books.
Phil
You didn't comment my Complementarity approach and ignoring Dirac's prognosis about sacrifice.
Price idea is boring.