I think he didn't quite understand the depth of Girard's thought. It's not like that you can really fight mimetic desire, especially not by following any kind of tactics. Reproducing behavior in a certain way is nothing but mimesis.
> Suppose that artificial intelligence research has succeeded in constructing a computer that behaves as if it understands Chinese. It takes Chinese characters as input and, by following the instructions of a computer program, produces other Chinese characters, which it presents as output. Suppose, says Searle, that this computer performs its task so convincingly that it comfortably passes the Turing test: it convinces a human Chinese speaker that the program is itself a live Chinese speaker.
> Searle then supposes that he is in a closed room and has a book with an English version of the computer program, along with sufficient papers, pencils, erasers, and filing cabinets. Searle could receive Chinese characters through a slot in the door, process them according to the program's instructions, and produce Chinese characters as output. If the computer had passed the Turing test this way, it follows, says Searle, that he would do so as well, simply by running the program manually.
The time dilation aspect in space travel is the most neglected in popular sci-fi. In many of these, there are intricate installations of some sort cryogenic sleep devices because the script authors assume that it takes you 150 years of travel at light speed to get to a place that is 150 light years away.
That's a very basic error, but I can't offhand remember coming across a story where the author made this mistake. After all, if the ship's top speed is even modestly below light speed the journey really could take many decades. Can you give an example?
I wasn't referring to the author in the article, but rather an unspecified collection of 'popular' SciFi, where this aspect is not explained. It is true that, even if you reach speeds of 0.5c you only get a ~15% time dilation.
Which is why most popular sci-fi franchises end up with velocity caps, justified either in-universe or out-of-universe. E.g. Star Trek sublight propulsion (impulse engine) has been established indirectly and through "word of God" to work with speeds up to ~1/3 c, which is not enough for relativistic effects to cause a big impact. The issue is conveniently omitted, because why travel fast through "normal space" when you have easy access to warp drive / jump drive / hyperdrive / wormholes, that gives you FTL and happens to drop you out into a convenient reference frame? And all the interesting action happens around planets anyway.
This omission makes it easy for the writers to introduce relativity as a nerdy plot point. For example, StarGate: Atlantis had an episode with a ship traveling absurdly close to the speed of light, which was devised as a convenient way to introduce characters that should've been dead for many thousands of years.
Interstellar explores this idea really well. Also see Andy Wiers' new book "Hail Mary", which I can thoroughly recommend. In Hail Mary he doesn't use cryogenics but a different mechanism.
The first three that come to mind are: Heinlein's "Time for the Stars", Haldeman's "The Forever War", and Anderson's "Tau Zero".
From those titles, a DDG search finds http://sf-encyclopedia.com/entry/relativity listing more, also containing the line "Very many sf stories use relativistic time dilation for one-way Time Travel into the future."
There are very few sci-fi movies or books where relativity is important and they treat it seriously. Tau Zero is one, I'm not sure about Time for the Stars, but Forever War does have FTL.
I created a list of all these works I could find a few years ago. Here is one link:
Virtually all of Larry Niven's novels that don't have FTL touch on this. Also shows up in most of Alastair Reynolds' novels, and in the Three Body Problem series.
alastair reynold's revelation space series certainly doesn't have ftl, apart from maybe [jumper clowns spoiler deleted]; the conjoiner drives use [science] to achieve 1g acceleration to get to near light speed, and time dilation is part of many of the plots.
> the conjoiner drives use [science] to achieve 1g acceleration to get to near light speed
For [science] read [magic], more or less, but yeah. In the very first stories they were Bussard ramjets, but this got retconned out (and a Bussard ramjet actually shows up in a later book as a failed experiment). In most of the books they're more or less applied magic, though.
This, incidentally, seems to be a common theme, as later discoveries tended to fall down on the side of Bussard ramjets not working (due to insufficient density etc). The last of Niven's Known Space books have some special pleading for how the pilot has to carefully direct the ramjet to get sufficient combustion volume, a detail that was never present in the old ones.
Time for the Stars has FTL at the end. (Physical FTL, that is. Telepathic FTL exists at the beginning.) But it's otherwise it's deliberately structured around the twin paradox - the main character is even a twin.
Indeed, while I remembered the importance of time dialation in Forever War , I didn't remember the FTL travel between collapsars.
I'm sure it has been, but I'm mainly talking about popular sci-fi movies. I'm sure you have at least one in mind where they have these 'sleep' devices.
I'm not much into visual media, so I can only come up with a few examples of 'sleep' devices:
Star Trek's "Space Seed" - 200 years in sublight stasis, no mention of speed or distance. Could be 0.5c for all we know. 100 ly at Enterprise's warp 6 cruising speed would take about 4 months, which seems not unreasonable.
The movie "Alien" - stasis, but seemingly with FTL given the times and distances involved. (https://avp.fandom.com/wiki/LV-223 says it was a 2 year voyage to the moon LV-223 in Prometheus.)
What came to my mind immediately was 'Passengers'. But, reading up the plot on Wikipedia, it is possible that it never actually was mentioned how far away the destination was or how fast they were going. So, maybe it wasn't a misconception on the sci-fi side, but on my side. For sure, any light speed travel shouldn't take any time and infinite amount of time should pass for the rest of the universe.
I mean yes, but there is a rather specific window where they make sense: at ~1-80% of c. Lower speeds it doesn't make sense to engage in interstellar travel at all, because even travelling 100s of years won't get you anywhere. At higher speeds it doesn't make sense because of time dilation.
But that's a... pretty important window. There are not-completely-bonkers hypothetical spacecraft designs that could get to, say, 0.2c. There's nothing particularly plausible that could get to 0.99c.
> Probably no reasonable human being would assume that Quantum Mechanic as we know it is the "holy grail" of physics.
Fully agreed. This, however, rests on the assumption that there is a 'holy grail' in physics (aka a theory of everything). It's a matter of taste, but I don't like that idea that there is a theory of everything because it doesn't seem reasonable that every last bit of our universe is explainable by a single theory. Why would that be? Seems like a conspiracy, if this was the case. To me, it's rather quite comforting to assume that there is something (be it the position and momentum of an electron) which we won't ever be able to understand because it just seams realistic. If this wasn't the case and we could show that there is a theory of everything I would immediately start my quest to find Morpheus to ask him to give me the right pill to wake up.
Depends on what other people do. If no one takes it I’ll take it. If everyone takes it I won’t take it. We need 50-80% vaccination rate overall. So, if I take the values of this survey which is at 70% vaccination rate at the moment, I would take it to be on the safe side.
Because others already questioned the first part, I’ll question this:
> the set of observations it offers is vast
Actually, in an experiment there is always only one observation at a time. That we group multiple observations together is kind of arbitrary and relies on the hope that the experimental conditions are the same and therefore one experiment is analogous to the next.
Yes, that's exactly the heart of the quote to me: There is sufficiently little complexity in the causality of observable behavior that with sufficiently controlled and repeated experiments/sampling, we can uncover regularities and patterns in it to fuel our predictions (and hypothesize about these causalities).
Does the reading of your multimeter depend on the digits of Arnold Schwarzenegger's phone number? Do you have to repeat the experiment if his phone number changes? Indeed, we assume that this is not an "experimental condition" to take into account. There is no way to determine this a-priori, and one could conceive of a universe with an arbitrary amount of such strange influences. But we do not appear to live in such a universe, which is why we get to apply Occam's Razor.
> Does the reading of your multimeter depend on the digits of Arnold Schwarzenegger's phone number? Do you have to repeat the experiment if his phone number changes? Indeed, we assume that this is not an "experimental condition" to take into account. There is no way to determine this a-priori, and one could conceive of a universe with an arbitrary amount of such strange influences. But we do not appear to live in such a universe, which is why we get to apply Occam's Razor.
I think this is not true for every experiment. For example if you measure the polarization of a photon it will have the same polarization in any subsequent experiment, no matter how hard you try to reduce complexity.
Also, my comment was rather directed at the fact that any experiment has a unique outcome. In that sense we we can’t have perfect control over an experiment, since at least time must have passed between subsequent measurements, such that the experimental conditions are different.
Because, a line doesn’t have any holes and a fraction just gives you a point, such that
no matter how close you are to another number there will always be gap.
Well, there is a gap in your answer, you speak about line, holes and points (domain of geometry, very well), but then you introduce numbers somehow. Also, I'd be more interested in relation between people, swearing and irrational numbers, not between irrational numbers and geometry. Unless you'll provide a mapping between geometry and people, that relates to irrational numbers.
Seems like one should write how the people who read your text would expect you to write. This is my main problem with writing, since I have a very hard time to figure out what people expect. I also read a lot of books about writing, but none really helped. They always use these very abstract concepts which if you apply them blindly will also lead to an incomprehensible text anyways. What helped a lot was to just take a similar text which seemingly fulfills expectations, and, almost short of plagiarism, just exchange the messages which are conveyed. This is where AI could help a lot, because I would think that it should be able to exactly this task, if you provide it the message you would like to write up. Anyways, I don’t know anybody (at least in science) who likes writing and I really hope that there will be a more practical solution than spending hours and hours of refining a text in the future. This time could better be spent on research.
Have you tried Steven Pinker's "Sense of Style"? Although there is indeed a chapter (ch.4) that deals with some difficult to apply concepts (i.e. adding unnecessary friction at the moment of writing), the other chapters delve into graspable topics with lots of examples that clearly explain what works and doesn't.
No, I haven’t read this one, maybe it’s worth a try. The issue is, even when you are at a stage where you realize what works and what doesn’t, you still wouldn’t know what to write exactly. The only option you have is to write up sentences, then check whether you made a mistake and, if so, write up a different sentence and reiterate. I would need a book which would tell me how to construct sentences which are in accordance with all the rules and concepts. But, it doesn’t seem to be possible to write such a book, since writing really is an art. After all, there also isn’t any book which teaches you how to paint like Da Vinci, but only those which tell you which rules you can apply to his paintings.
For those who wonder what the bottom line in the article is why time isn’t just another dimension: There is a minus sign and the speed of light in front of time in the space-time metric. It is argued that the minus sign comes about because time is imaginary (in complex number terms). I don’t find this convincing. One could still argue that time is just an ordinary dimension and the structure of the metric is just a property of how we measure distances.
> There is a minus sign and the speed of light in front of time in the space-time metric.
Yes, that's called the Minkowski metric, and it's absolutely nothing new.
You can do the exact same physics with the opposite sign convention (called the signature of the metric), where time has a positive sign and all three spatial dimensions have negative signs; the only rule is that time has to be the odd one out, so rotations in a space-time plane obey hyperbolic geometry as opposed to Euclidean. You can get rid of the factor of c by moving to a different system of units, commonly called the natural units, where the speed of light is 1.
All of this is covered in any real introduction to Special Relativity, which, in turn, is at the beginning of any course on Modern Physics, as opposed to the Newtonian Physics.
You're right in that the article doesn't quite "explain" it .. and it cannot be explained relative to normal newtonian "intuition". Working with Maxwell's equations to understand how electric fields can transform to magnetic fields and vice versa, working out the "wave equation" and seeing the speed of electromagnetic waves emerge from the equation independent of the reference frame was what nailed it for me.
Let’s not forget that Maxwell equations are shaped as such due to the respective algebra. In clifford algebric spaces it is simply one equation.
One idea is that not only it is important to conceptualize a complex phenomenon but to also whether we can formalize it in a simple way.
"simply one equation" that expands to the same set of vector equations which expands to the coordinate-system-specific equations.
∂F=J (barring constants) is a beautiful restatement, but I think it puts the cart before the horse to focus on it because that formulation is possible because of the invariances that hold and that comes from the raw Maxwell's equations .. at least historically.
The abstract formalisation is even harder to convey (at least for me, and so far) since it takes away the familiar "electricity" and "magnetism" and you need to think about the more complex F that combines both. One way perhaps is to start with circuits - which are discrete and circuit laws can be expressed with the same equation and then argue for the continuous case .. but speed of light invariance would still be a long way from that compared to the raw Maxwell's equations route.
> One could still argue that time is just an ordinary dimension and the structure of the metric is just a property of how we measure distances.
The math doesn't work unless time is different from the 3 spatial dimensions. In particular, distances in space-time can be negative, unlike distances in space.
Well, I'm just arguing that it isn't clear whether this prefactor (that shows up in the metric in front of time) is a property of time or a property of the metric. It is pretty clear that the math wouldn't work if the prefactor was different, though.
Given that there is a physical difference between events separated by positive and negative distances in spacetime, I think it's pretty clear that the prefactor is a property of spacetime.
Yes, it is mostly semantics but the question really is what you think the space-time metric is. In order to attribute the prefactor to time you would need to argue that the space-time metric really is Euclidean, but because time is different from space there is this negative prefactor showing up in the metric. But you can also claim that time and space are the same and the space time metric is hyperbolic. Since there is there is no good argument why metrics necessarily need to be Euclidean, I find the second option more convincing.
Not at all - spacetime is real, but it is not a 4-dimensional Cartesian coordinate system where all 4 dimensions are of the same kind. For example, for any two events that are time-like separated, any two observers will agree on the order in which they happen, whereas for two events that are space-like separated, there will be observers that see these two events happen in either order. Time is different from space, though they are related.
Note that if the space intervals are all zero and the time interval is unit time or 1, the spacetime displacement is equal to C. Thus when at rest physically we progress though the time dimension at the speed of light. Conversely if two points are separated by an interval equal to C, their distance in the time dimension is zero.
The latter result isn't really a surprise, we all know time doesn't pass if you're traveling at light speed, but IMHO it's interesting to see how it arises from the geometry.
> if two points are separated by an interval equal to C
If d = c, I don't think it determines the values of x, y, z, and t. What if x = 2c, y = z = 0, and t = 1? Unless I'm not following your logic correctly. In my recollection, for two given points in spacetime, d is invariant but the values of x, y, z, and t depend on the observer's frame of reference.
From the point of view of the photons, yes. From the point of view of everything else, no.
One of the bits of relativity that took me the longest to become aware of was that “right now” isn’t even meaningfully and universally defined within it.
What about my point of view? He said that if my eyes and the sun are separated by X light seconds, then X seconds later sun and my eyes are at time distance of zero
This is for an observer following a trajectory in space time. So for an observer covering a distance at light speed the time interval is zero. For other observers on different trajectories, such as stationary in the space coordinates, that will not be the case.
This seems odd because there clearly time dilation effects between two observers even when they are not accelerating but merely have a large difference in relative constant speed.
You seem to be saying that there has to be constant acceleration between observers for this effect to take place.
My apologies I really didn’t explain myself very well at all. That was quite confusing. This formula represents a trajectory in spacetime with respect to some frame of reference of an observer. As with any trajectory it has space and time components.
The x, y, z deltas are your displacement through space in those dimensions relative to some frame of reference (of an observer, presumably) and t is the time component. If the space deltas are all zero then you are at rest relative to that inertial frame. You are not accelerating or moving and your motion through the time dimension in unit time, according to this formula, is C. This is odd because C is normally thought of as a motion through space, but in this case your not moving through space (in the reference frame).
