That concept is merely an untested (it didn't pass the rational method) philosophical proposition. It also completely ignores evolution and what it can possibly offer in a few million years to a surviving intelligent species. Being a philosophical proposition it also can't be proposed as a law, much less one that can't be violated.
Let's leave philosophy (which I adore, mind you) to those areas where its relationship with science can be useful.
Originally Posted by brewbuck:
Reimplementing a large system in another language to get a 25% performance boost is nonsense. It would be cheaper to just get a computer which is 25% faster.
At some point you missed the point.
Originally Posted by brewbuck:
Reimplementing a large system in another language to get a 25% performance boost is nonsense. It would be cheaper to just get a computer which is 25% faster.
I think physics doesn't so much describe the physical world as it describes our model of it. Every once in a while,
experimental physics throws a monkey wrench into the model and we wind up with a new or revised model. Maxwell's
electromagnetic field equations did just this. Often it gives us more new things to explain than it answers.
The "twin paradox" may not be science in the usual sense (providing an experimental result), but Thought Experiments
are science. A Thought Experiment has some serious requirements. It must be based on accepted laws of physics; it
cannot violate any. It needs to obvious or at least determinable that the Thought Experiment would proceed exactly as
the real experiment would, if it could be performed. A Thought Experiment is used where the actual experiment would
be impossible for practical or technical reasons.
It was partly the simplicity of Einstein's "bouncing photon clock" that was responsible for it's wide acceptance. It involved
nothing more than the Principle of Relativity (relative motion) and the observed constancy of light speed (both of these
principles were already widely accepted, but at odds with each other). The experimental results of that Thought Experiment
became the Special Theory of Relativity.
Last edited by megafiddle; 01-13-2013 at 08:33 PM.
But to answer your original question, "...To that end we say that the travelling twin experienced acceleration. But what exactly
experienced acceleration?
I'm not interested in the paradox per se. What I'm interested in understanding is exactly what force allows for a system (the
travelling twin, for instance) to be considered a single unit and to experience the effect of time dilation as a whole...",
There are two aspects of the time dilation effect. One of these is described by Special Relativity and is what I would
call nonpersistant. These effects do not persist when the two clocks are reunited and compared. The effect only
exists while the clocks are observed in motion relative to each other. My "symmetrically orbiting twins" thought experiment
in an earlier post illustrates this.
This aspect of time dilation is a matter of perspective, it is how the universe appears to an observer in relative motion.
But the concept of an observed effect should not be mistaken for an illusion. Observation is the same concept as used in
performing any experiment and evaluating the results. It is not just what we see; it is physical reality in the same sense as
any other experimental observation. When the "stationary" and "travelling" clocks are reunited, the relative motion is no longer
there, and neither is the time dilation. The perspective view of spacetime is now different.
The other aspect of time dilation is described by General Relativity, and is what I would call persistant. When reunited
and compared, the clocks will show an elapsed time discrepency. The travelling twin does indeed experience a force, an
accelerating force, although I'm not sure that it is a force in the same sense that you meant it.
If an object is falling above a planet, it experiences no force. Yet it accelerates. The reason is that the force is distributed
evenly (ignoring tidal force) among the entire mass of the object. There is nothing resisting the acceleration. If the object
is sitting on the surface of the planet, however, the surface is resisting the accelerating force. So the object experiences
weight. In the case of an object sitting on a gravitational mass, or an object being accelerating through space, both
experience accelerating forces and both experience persistant time dilation.
However, I think the accelerating force is not the cause of time dilation, but just another effect of being within a curved
section of spacetime. It is the curvature that causes the accelerating force. And it is within this curvature that time
progresses more slowly.
Last edited by megafiddle; 01-13-2013 at 10:26 PM.
I'm not sure what a model may mean in this context(*), but Physics strives to make us understand how the universe behaves. It's really a wide-encompassing field, full of complexity, but really easy to generally describe. There's no mystery to its purpose. No second meaning either.
The trouble is that the universe has been consistently shown to exist and behave in ways that transcend our senses -- lately, also our cognitive abilities to understand it.
It's easy to come up with false color images to show light in all its variety, considering the greatly limited band our eyes can perceive. But its a first step to understand how our universe exists in domains that exceed our senses. Other physical realities are however much harder to model and may never have a proper representation. While an atom can be exactly represented as a mathematical entity (a mathematical model if you may), it probably will forever be beyond our sensory and cognitive capacities to come up with a visual entity that better describes it. Exactly because it exists in a "place" outside that domain.
Meanwhile we have been developing scientific fields that go well beyond these limitations and into newer areas that completely challenge our cognitive abilities. Quantum Theory is such a branch of physics, in which men like Heisenberg, Bohr, Schrodinger and Feynman have been known to openly and gladly admit we cannot understand it. The science is way beyond our available tools to explain it. Even Thought Experiments show their limitations when it comes to explaining its theories. And yet, Quantum Physics, despite its almost wizardly reputation, has been consistently shown to produce sound theories that stand peer review and have been proven consistent over and over again. It seems to be true than that the universe exists and behaves too on a level well beyond our ability to properly understand it.
So.. my earlier post (and this one as an extension to that) was all in reply to C_ntua justifiable annoyance that later branches of physics have been consistently introducing into our understanding of the universe a reality that is becoming harder and harder to understand. That is so because the universe really exists beyond our capacity to fully understand it. It's not terrible, shouldn't be heart breaking, and it's not humiliating, to assume that we may need to climb a few more steps in the evolutionary ladder to better understand our universe. The progression of Science is deeply tied to our evolutionary pattern. Has in the past and will be in the future.
Again, no. Thought Experiments aren't science! Really, we need to get that right. It's a dangerous road that one with the potential to damage even more the already shaken credibility of science in the public eye.
Thought Experiments.
This says nothing about the actual science that took place to properly demonstrate the theory. The thought experiment was simply a verbal device that helped producing a scientific theory, because there was no way at the time to properly apply the scientific method. The theory was accepted, but put on hold until properly demonstrated. Thought experiments can certainly end up producing new theories. But in themselves they are nothing more than an exercise of the Rational Method, not the Scientific Method.
Originally Posted by brewbuck:
Reimplementing a large system in another language to get a 25% performance boost is nonsense. It would be cheaper to just get a computer which is 25% faster.
I agree with Mario F
The scientific method uses both Deductive Logic and Inductive Reasoning.
Deductive Logic starts with one or more premises -> Things that the researcher assumes is true
"Gumtrees are Plants" (premise 1)
"All plants produce energy through photosynthesis" (premise 2)
"Then Gumtrees must produce energy through photosynthesis" (conclusion)
If one of these premises are false, then all post conclusions are compromised - "The world is flat" is often a good example of this.
Inductive Reasoning is based on what has been observed to draw conclusions about things. This is usually done by experiments and measuring the outcomes of the experiments. For example: 100% of my peanut-butter on toast fell on the floor peanut-butter side down; therefore it is likely to always fall that side down.
The Scientific Method requires a defined problem, a hypothesis (which if confirmed, solved the problem), gathering of data, and analysing the data to see whether it supported the hypothesis or not.
A hypothesis from the peanut butter experiment may be that one side of the bread may be heavier ->
"When things fall, the heavier side will orientate itself closer to the ground"
"The Peanut-Butter side is heavier"
"When the Peanut-Butter on toast falls to the ground, the Peanut-Butter side will orientate itself closer to the ground"
However, marking both sides with coloured pens (making the colours different to tell the different sides apart, whilst keeping the weight equal) will debunk this hypothesis - It's because there is a problem with the first premise.
Without experimental results supporting your Hypothesis, you have a chance of being wrong - And if someone else uses your assumption to build another assumption... well...
Fact - Beethoven wrote his first symphony in C
I would agree that Thought Experiments are not scientific method, and are not an scientific experimment.
But it seems they can be scientifically valid, if properly constructed. Even physical experiments require
logic and reasoning to arrive at a result. If no additional data or facts are required, beyond what is already
given, then shouldn't logic and reasoning provide a scientifically valid result?
Are you asking if all Deductive Logic premises are backed up with Inductive Reasoning - Is the result valid?
I don't believe that this is always true, because there could be another reason for an experiment agreeing with the hypothesis that the person conducting the initial research didn't think of.
The actual reason for the toast always landing spread side down is usually put down to the hight of the table -> If the experiment was conducted on a different sized table, the data may accidentally support a wrong hypothesis (When I removed the weight from one side, the landing orientation became unpredictable: Therefore, the reason the toast always lands spread down is because of one side being heavier than the other)
Fact - Beethoven wrote his first symphony in C
That is akin to applying a Rational Method (Rational Argument, as known to philosophy) to science. It can't do.
Not at least in the context of Thought Experiments. Because they make no concessions to the natural laws. A Thought Experiment is only scientific valid in its logical domain and exists only as a logical abstraction. It won't be valid anywhere else. Demons don't really exist (apparently) that can manipulate machinery at the speed of light, a cat cannot be confirmed to both dead and alive, an athlete carrying a pole cannot run at the speed of light. This may or may not have an effect on the validity of a Thought Experiment as a source for a scientific result. While Albert Einstein was able to successfully develop a theory through a Thought Experiment, he was also able to be proven completely wrong with another; on his infamous EPR paper.
I would argue that we can successfully apply logic and reasoning while analyzing a scientific result. That will do. And its been sorely lacking on many of our universities and what students and their teachers have been doing with their grants. Studying 100 random people, no matter how valid is the scientific method applied, does not make the result necessarily universal to the human race. There's been an overabundance of statistics and very little science in many of our universities. At least judging by the media.
Originally Posted by brewbuck:
Reimplementing a large system in another language to get a 25% performance boost is nonsense. It would be cheaper to just get a computer which is 25% faster.
A Thought Experiment is a Hypothesis - Nothing more. And a Hypothesis is not a scientific fact.
"scientific fact" from Dictionary.com
"Definition: Any observation that has been repeatedly confirmed and accepted as true; any scientific observation that has not been refuted"
You build your Hypothesis from Scientific Fact, but it in itself does not become Scientific Fact until it can predict an observation in the real world.
The movie "The Matrix" has a very convincing argument. In fact, there would be a lot of Sci-fi which could be roped in as arguments logically put forward - But none of them Scientific Fact.
Last edited by Click_here; 01-15-2013 at 10:20 PM.
Fact - Beethoven wrote his first symphony in C
It's an observed concept. I imagine trying to test it would produce far less promising results than said simple observation of it. This seems to hold true for any stance on qualia.
Even if the evolution you speak of was true, closure would still hold true because said evolution isn't driven by ourselves.
When unwound, all reason will eventually fall on to "philosophical propositions", so labelling my argument as such is not sufficient reason to dismiss it.