Magic and Sci-Fi

Tom Kalbfus said:
One reason to use magic is as a substitute for the Jump Drive. The Jump Drive defies physics as we know it,

Actually it doesn't defy physics as we know it. Physics (rules of our universe) doesn't cover other universes. That is why the "jump" drive was used. It AVOIDS defying physics as we know it..
 
Tom Kalbfus said:
Getting to that other universe is what defies physics.

That's arguable. The fact is we have an incomplete understanding of physics. There are gaps in our understanding of relativity, quantum mechanics and in particular the cases where the predictions of those two theories intersect and differ. Therefore there may well be phenomena that are ruled out by our current understanding of physics, but which are possible, and it's hard to be sure what they are.

Now personally I don't think anything like the Alcubierre drive is going to turn out to be physically possible, but it's an interesting example of an edge case where currently it's not actually possible for us to rule it out definitively at a nuts-n-bolts technical level. However at a higher level we can say that if it, or something like Jump Drive, is possible then we do know that they would allow violations of causality (basically time travel). That's the level at which I doubt the viability of any FTL system in reality, not the detailed technicalities of how it might work at the physical level.

Getting back to the issue of magic.

In the pre-scientific era people may not have specifically listed and reasoned about formal laws of magic, but then again if you look at what people actually did and believed to be true we can see that they absolutely did believe in things like sympathy, synchronicity, contagion, etc. Just look at what people believed about Saint's relics, the Talmudic rules about ritual purity, Egyptian funerary practices, etc. Formulation of these 'laws' of magic was based on observing what people actually believed or practiced and then deriving formal laws from that. This is exactly how science works, of course.

Which goes to my next point, which is that if the laws of the universe allow 'magic', then by definition those laws of the universe are physical laws in the literal sense. The only reason that nowadays we distinguish between 'science' and 'magic' is because the scientific method has given us tools to distinguish between beliefs (let's call them 'theories') that work in the real world and ones that don't. However if 'magical' practices were to work, they would of course become part of the category of beliefs, or theories, that are provable and therefore would be considered 'scientific'.

In a universe in which a person can actually cast a spell and levitate or become invisible, arbitrarily categorizing that as being 'unscientific' is just fuzzy thinking. If you can perform that experiment and validate it according to the scientific method, then what you are doing is science. Isaac Newton was fascinated by alchemy and what we would now call the occult and applied scientific methods to investigate them. He did not think of them as being different from any of his other experiments. If those experiments had worked, would he have stopped being a scientist and started being a magician? If his treatises on mechanics had also included experimental results involving 'magical' manipulation of objects right alongside his equations of force, mass and acceleration would it have been a physics text, a Grimoire, or both?

To my mind, an SF setting that includes magic is just an SF setting in which there are a few more, and quite possible a few missing laws of physics compared to our world. Traditionally we allow certain variations from known physical laws or principles in our SF (ignoring causality violations, setting aside thermodynamics, etc). If you also want to add in some additional laws that in our universe are considered magical, then go for it, but I think if you try and pretend that these are still separate from the other laws of your universe and fall under some special different category, then I think you're making a lot more work for yourself in terms of explaining how that can be and what the consequences of that are.

Simon Hibbs
 
"Magic" is any effects that are not explainable by current understanding of the laws of the Universe. Now if someone were to cast a "Spell" and something specific were to happen, the analogy would be typing in a command word on your computer that activates a specific program that does something specific. Now the person casting the spell doesn't really know how magic works, he just knows which words, incantations and gestures activate a certain effect that occurs for which their is no current scientific explanation, that is how I would define "Magic" in a Traveller setting, where the person learned to cast the spell in the first place is a mystery, because societies of wizards are very secretive and do not reveal their original sources in order to guard their exclusive monopoly to this power.
 
Tom Kalbfus said:
"Magic" is any effects that are not explainable by current understanding of the laws of the Universe. ...

If by current, you mean current for the characters in their far future SF setting, with their considerably more advanced understanding of Physics relative to ours, then sure that's one way to go. Magic could be this new, relatively unknown thing that has only recently come to light, perhaps practiced by a distant alien species, or discovered in texts left by a long extinct civilization. That might explain why it's not been investigated scientifically and integrated into scientific thought in the setting. But the very first thing that's going to happen when it's discovered is that scientists are going to be all over it like a nasty rash figuring out how and why it works, and what the implications are for current scientific theories.

Simon Hibbs
 
Tom Kalbfus said:
"Magic" is any effects that are not explainable by current understanding of the laws of the Universe.

In games, I define it as that which has no scientific basis (IRL or even sci-fi) but is fantasy. E.G. psionics in Trav. There is no sci-fi (science based) explanation or reason. Humans just think the right thoughts and can teleport matter. No matter how far advanced our science, you & I cannot do that as scientific advancement isn't why it works in Trav. Ergo, it's magic.
 
FTL is one of a host of impossibilities which are accepted in Traveller. Basically, despite the "hard SF" label, you don't get to cherry-pick the impossibilities in the game.

Actually, more to the point, you can only cherry-pick your own impossibilities. No matter how loudly people may complain, and risk moderator attention through aggressive words, nobody has the right to tell anybody else what can and cannot be done in their game of Traveller.

If players want magic in their SF universe - which is a theme covered by a good many SF authors such as Lyndon Hardy, L Sprague DeCamp, Isaac Asimov, Arthur C Clarke and Larry Niven, not to mention magic's appearances in The ABC Warriors, Strontium Dog and Judge Dredd - they can have magic in their game. It doesn't impact on your hard-SF game, and despite what you might think, your Traveller Universe is still not the Official Traveller Universe either.
 
The rule of thumb in hard SF is that you are allowed one or two improbable things that you handwave (such as FTL travel or artificial gravity), but you should rigorously explore the consequences of these technologies. Traveller is unusual in that it is quite hard in some respects (e.g. no blasters or similar energy weapons) but quite soft in others (*cough* Psionics *cough*). This is largely because it reflects the assumptions of literary SF from before the 1970s. There's nothing wrong with that, but it is a bit unusual. I'd also argue that Traveller doesn't really explore the consequences of the adopted FTL technology in great depth - it's simply a mechanism to allow easy travel between star systems. Actually, I'd love to see a Stardrive sourcebook for Traveller that does this and provides expanded rules for alternative approaches (eg hyperdrive, warp drive, stargates, wormholes, etc).
 
alex_greene said:
FTL is one of a host of impossibilities which are accepted in Traveller.

There is no FTL in Traveller. There IS a way around having to have FLT. Which doesn't violate physical laws as we know them. It may or may not be possible. It is currently unknown. (aka classic sci-fi)
 
Prime_Evil said:
Traveller is unusual in that it is quite hard in some respects (e.g. no blasters or similar energy weapons) but quite soft in others (*cough* Psionics *cough*).
PMFJI but... aren't Energy Weapons (Core Rule book, page 100) blasters?

:)
 
IanBruntlett said:
Prime_Evil said:
Traveller is unusual in that it is quite hard in some respects (e.g. no blasters or similar energy weapons) but quite soft in others (*cough* Psionics *cough*).
PMFJI but... aren't Energy Weapons (Core Rule book, page 100) blasters?

:)
Blasters are just a slang term
 
sideranautae said:
alex_greene said:
FTL is one of a host of impossibilities which are accepted in Traveller.

There is no FTL in Traveller. There IS a way around having to have FLT. Which doesn't violate physical laws as we know them. It may or may not be possible. It is currently unknown. (aka classic sci-fi)

If you arrive at your destination before light traveling through a vacuum could have done, then you have traveled faster than light. Whether or not you physically transited the space in between doesn't matter, it still means there will be some frames of reference in which the ship arrived before it left. Therefore in those frames of reference information could have been transmitted from destination to origin before the ship left, which violates causality.

There's no way around it*, sorry.

Simon Hibbs

*Edit: It depends on whether you think of non-violation of causality as a physical law. It's technically an axiom. As the saying goes: Relativity, Causality, FTL. Choose two. Traditionally in SF we choose causality and FTL, and just pay very selective lip service to relativity.
 
simonh said:
If you arrive at your destination before light traveling through a vacuum could have done, then you have traveled faster than light. Whether or not you physically transited the space in between doesn't matter, it still means there will be some frames of reference in which the ship arrived before it left.
Or perhaps the ship is seen to arrive before it is perceived to have left. In Traveller the ship still arrives after it left, by the frame of reference of the world of departure, even if only one week later rather than 3+ years later.
 
simonh said:
If you arrive at your destination before light traveling through a vacuum could have done, then you have traveled faster than light. Whether or not you physically transited the space in between doesn't matter, it still means there will be some frames of reference in which the ship arrived before it left.

There would only be ONE ship using a J-drive. It isn't replicated and doesn't appear in N-space at two different locations at the same time. That is like saying that a jet that is supersonic is at two places at the same time just because you hear it where it physically isn't. Traveling means covering (traversing) a distance in a universe. J-drives traverse J-space, not N-space. So, you don't travel FTL. That is only an apparency. You must use physics definitions when talking of this. Not mundane. Otherwise you come to incorrect conclusions.
 
sideranautae said:
simonh said:
If you arrive at your destination before light traveling through a vacuum could have done, then you have traveled faster than light. Whether or not you physically transited the space in between doesn't matter, it still means there will be some frames of reference in which the ship arrived before it left.

There would only be ONE ship using a J-drive. It isn't replicated and doesn't appear in N-space at two different locations at the same time. That is like saying that a jet that is supersonic is at two places at the same time just because you hear it where it physically isn't. Traveling means covering (traversing) a distance in a universe. J-drives traverse J-space, not N-space. So, you don't travel FTL. That is only an apparency. You must use physics definitions when talking of this. Not mundane. Otherwise you come to incorrect conclusions.

You are the one to come to incorrect conclusions. A J-drive like the one in Traveller would - in our reality - violate causality. There is no way around it.

Fortunately, the Traveller reality is not our reality, and an easy way around the causality problem is to postulate a preferred frame of reference.
 
Pyromancer said:
You are the one to come to incorrect conclusions. A J-drive like the one in Traveller would - in our reality - violate causality. There is no way around it.

Um, no. http://en.wikipedia.org/wiki/Causality_%28physics%29

It no more violates it than if you bounced an image of a ship around the universe from point A and a ship took a direct route and beat the bounced image to the point B. You haven't shown any violation of causality within the appropriate framework.
 
sideranautae said:
Pyromancer said:
You are the one to come to incorrect conclusions. A J-drive like the one in Traveller would - in our reality - violate causality. There is no way around it.

Um, no. http://en.wikipedia.org/wiki/Causality_%28physics%29

It no more violates it than if you bounced an image of a ship around the universe from point A and a ship took a direct route and beat the bounced image to the point B. You haven't shown any violation of causality within the appropriate framework.

Quoting from the wikipedia article you linked to:

In modern physics, the notion of causality had to be clarified. The insights of the theory of special relativity confirmed the assumption of causality, but they made the meaning of the word "simultaneous" observer-dependent.[5] Consequently, the relativistic principle of causality says that the cause must precede its effect according to all inertial observers. This is equivalent to the statement that the cause and its effect are separated by a timelike interval, and the effect belongs to the future of its cause. If a timelike interval separates the two events, this means that a signal could be sent between them at less than the speed of light. On the other hand, if signals could move faster than the speed of light, this would violate causality because it would allow a signal to be sent across spacelike intervals, which means that at least to some inertial observers the signal would travel backward in time. For this reason, special relativity does not allow communication faster than the speed of light.

There is no intertial frame of reference in which a signal propagating at less than the speed of light could travel from the event of when a ship went into jump, and arrive at the event of it emerging from jump at a nearby star system.

Therefore a ship with a jump drive could carry a signal to it's destination faster than the speed of light, across a spacelike interval, which would open up the possibility of causality violations.

To dig into why, we'd really need to start discussing light cones, Minkowski diagrams, Lorenz transformations etc. This is degree level physics, which I did study as a student, but it was a very long time ago. I find it helps to think about the speed of light as being the speed of simultaneity.

Simon Hibbs
 
simonh said:
Therefore a ship with a jump drive could carry a signal to it's destination faster than the speed of light, across a spacelike interval, which would open up the possibility of causality violations.

I too studied this. There is no violation if the object didn't have a "violation" by action in THIS universe. That was my point... J-space isn't subject to the laws we know as physics.
 
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