otherwise I could easily use the double slit experiment or any other simple experiment of a quantum mechanical nature to send messages to myself in the past and win the lottery

You should try, just in case

The closest thing you can get to it is the quantum eraser experiment, which is spooky, but still doesn't involve changing the past.  At least not in any meaningful or useful way.   Rather, it's a very trippy example of how the universe is amazingly well set up to prevent you from doing such a thing.

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Also I have actually done the double slit experiment (with single photons at a time) in the lab, and it was extremely fun and a bit mind breaking.  There are many many many interpretations for "what is going on" behind that experiment, and I have come to my own pseudo-conclusion which is just as much metaphysics as the others.  Still, I am more of a fan of "shut up and calculate" when it comes to applying quantum mechanics to solve problems or predict the outcomes of experiments.

Wat- why is it then said that the quantum mechanical arrow of time is different from our arrow of time?  Also according to the different interpretations of quantum mechanics, isn't wave function collapse explained differently in different versions where in some you have branching out into other universes (so paradoxes dont occur.)  Also, in the sense of space or time entanglement, tunneling or teleportation (which has been reported to occur at much faster than c) how can that be explained without breaking down space and time at the very basic levels?  According to Loop Quantum Cosmology space-time consists of discrete units, but then what exists at the subplanck level?

And how do you feel about different universes having different arrows of time relative to each other (this would conserve time symmetry on an omniverse scale.)

Oops saw you made some new posts so I will add here.  If we did end up changing the past we would never know it because we would not have a memory of the changes that were made.  Or it would be in a different universe with the original timeline intact.  In my own view, all timelines emerged at each big bounce and converge again at the next one and all pasts, presents and futures coexist like a road thats already been laid out.


Stellarator, the idea of exotic life forms is pretty interesting, on multiple levels, and we might be biased in our ideas in how intelligence evolves.

What about the idea of hive or collective minds?  Can species technologically evolve that have a hive mentality?  When I mentioned beings of energy or consisting of sentient dust roaming through the universe I was also thinking about the complex organic matter we've found in interstellar space- that's pretty fascinating!  Can intelligence evolve to include an entire planet or something even greater all working together- like Isaac Asimov's Gaia or Galaxia?  What a wonderful concept/idea!

I also find it intriguing that right here on Earth, we have so-called simple slime molds that create structures reminiscent of our own architecture, like our subway systems for example.  We all seem to abide by the same general principles.  Even the structure of the universe seems to resemble the structure of the human brain on a very large cosmic scale.  Perhaps, as Carl Sagan once said, the universe did create us (and others) in order to understand itself better.  And perhaps others do also.

Oh that sucks, I was editing my post and I lost it because the amount of time it took to edit it made me go back to the check-in screen that controls spam ugh- so I will just put it in a new post here.

Wat-

If causality must always be maintained then for the warp drive to work there will have to be a multidimensional way of leaving space-time at one point within a bubble  and re-entering it at a different point.  That would apply to time machines also.  Is that how the Alcubierre drive maintains causality?  Also we talked about this previously- what about a black hole drive?

Stellator-

I like the idea of Great Filters or hurdles and was wondering had the K-T collision not occurred would we have evolved 65 million years ago and from reptiles instead of mammals?  Imagine where we'd be today.  Probably making our own universes and travelling back and forth between them haha.  That's why I think an advanced civilization even a few thousand years ahead of us would be undetectable by us- as Carl Sagan said, a highly advanced (Kardashev III) civilization would be indistinguishable from background natural forces and may even be able to create their own universes.  Makes you wonder where ours came from.  Meanwhile we are a lowly Level 0.7, and according to that scale, not even expected to develop a warp drive for 7,500 years.  If we ever ran into one of these highly advanced civilizations, I wonder whether we could even comprehend their science, or would it seem like magic to us?  At the very least they'd be able to cloak themselves so we wouldn't be able to detect them at all.  Thats what I meant by a civilization being able to manipulate space-time.  Our own military has some cloaking technology, albeit very primitive compared to what I am envisioning.

Also according to the different interpretations of quantum mechanics, isn't wave function collapse explained differently in different versions where in some you have branching out into other universes (so paradoxes dont occur.)

Yes, it's an interpretation. :)  That does not make it true.  There are tons of interpretations of quantum mechanics.  

The many worlds interpretation you're referencing is also not a method for avoiding causal paradoxes.  It simply says that every possible measurement of a system is realized, just in other universes.  In the technical jargon, when we "measure a quantum system", its wave function collapses to one of its eigenvalues (of which there might be an infinite number or continuum.)  The eigenvalue is the observed quantity -- perhaps the energy, or position, or momentum.  Many worlds interpretation says that wave function collapse does not simply choose one of the eigenvalues.  It chooses all of them, each one in a different universe.

Personally, I don't like many worlds interpretation.  It doesn't really explain anything.  It's just a cute way of thinking about wave function collapse.

 Also, in the sense of space or time entanglement, tunneling or teleportation (which has been reported to occur at much faster than c) how can that be explained without breaking down space and time at the very basic levels?

Wave function collapse is instantaneous (to the extent that observations have constrained it), but it does not transfer information!  So it does not violate causality.  This is highly related to the quantum eraser experiment I linked to.

Another example:  it is quite common to encounter waves that have a phase velocity faster than c.  But phase velocity of a wave is not what carries information.  That's the group velocity, which is always slower or equal to c.  (Actually there are some unusual cases where you can get group velocity faster than c, but only in highly lossy media which make it impossible to use for breaking causality anyway.)



To reiterate, causality is a deep principle that stems from logic more so than any physical law.  To have physics without causality is basically to not even have physics.  You can try to think of all sorts of creative ways to violate causality.  But if you think about it, you'll find those lead to nonsensical situations, and if you do experiments, you find the universe is incredibly good at preventing it.  To such an amazingly thorough degree that it almost becomes freaky.

Thanks for the advice about saving my posts lol it saved my bacon!

I think there are two things are play with why the universe does this.  One would be that our own memories are altered so we just dont know of a past that was different from the one we remember.  The other is that the universe, being an apparently closed system (not including whatever influences other universes might have on the CMBR) is a closed system and being a part of the universe we by definition must obey causality (on the macro level anyway.)  Therefore not to have causality on the macro level would by definition mean that we had left the universe.  Thats why I think any kind of warp/time drive will need to involve some kind of higher dimensional physics/other universes, etc.

I remember you, Doc and I talked about these interpretations awhile back.  I liked pilot wave theory.  

It's interesting we were talking about teleportation earlier today and I recall reading some sci fi works when I was little which involved teleportation.  In them the host was invariably destroyed.  Do you think if we ever achieve teleportation on human level scales it will necessarily cause the original to be destroyed?  And why would that be.  The last I had read we had been able to teleport molecules across a distance of approximately 20 miles.

It's interesting that as highly intelligent species, one of the valued qualities of that is to be able to alter the environment.  That isn't always positive.  Humanity's population has reached the point where we are crowding out other species and adversely affecting our own health and environment.  Asthma and food allergies have now become commonplace because of pollutants and chemicals used in our foods.  Climate change can also be directly connected to human overpopulation.  Higher stress levels, sleeplessness, depression, cancer, various congenital ailments, autism, ADHD, etc., can also be connected to how we live, what we eat and the types of stimuli bombard our sensory equipment on a daily basis.

What about the idea of hive or collective minds?  Can species technologically evolve that have a hive mentality?

Yes, something like that could evolve, but that doesn't mean they wouldn't follow any of the natural laws as outlined above, and thus allow us to detect it!

would we have evolved 65 million years ago and from reptiles instead of mammals?

Certainly it would seem like the members of the Troodontidae appear as though they were going in that evolutionary direction. It is difficult to extrapolate of course. Needless to say though, they would NOT look like this:

But rather, might look more like this, as depicted in this sci-fi:


Primates look the way we do because of millions of years of arboreal living in trees that favors long limbs. When the forest shrunk about 5 million years ago, we had to straighten up and stand upright to watch for predators better, since there were fewer trees to hide in. Very specific evolutionary paths made us what we are today, all other features are circumspect or from older lineages, who's features survived in us due to their usefulness. Thus, why would any theropod evolve to a primate body-type? All an intelligent being needs to have are sophisticated biological means of manipulating tools free of locomotive tasks (hands - not necessarily with opposable thumbs - or fingers at all, as we can see with octopi and intelligent birds), a big enough brain to actually understand the world around them in a sentient way, along with sensory abilities and of course an environment that allows them to evolve without constantly being harried by apex predators. In his 1977 book, The Dragons of Eden: Speculations on the Evolution of Human Intelligence, Carl Sagan speculated about the related troodontid genus Saurornithoides evolving into intelligence. I'd highly suggest checking out that book. Among other things, Sagan thought that their arithmetic would be Base 8 (octal) rather than Base 10 (decimal).

It would also be good to bear in mind that primates as we know them could still have evolved. Nothing says apes couldn't have survived in an arboreal wilderness dominated by swooping microraptors in the trees and tyrannosaurs stalking the ground below.

I love Carl Sagan's books and movies but haven't read that one yet!  Base 8 because they had 8 fingers?  It's interesting that they'd still have tails- perhaps those would go away with time also or were they needed for balance?

Question is even if primates evolved in that kind of environment, would they have evolved further into humans or would they have always remained just arboreal creatures, safe in the trees rather than venture onto the ground?

I forgot to mention squid among the list of extremely intelligent creatures that show emotion and even communicate with each other by changing color and are very social creatures with large and complex eyes (giant squid actually have the largest eyes we know of.)

Question is even if primates evolved in that kind of environment, would they have evolved further into humans or would they have always remained just arboreal creatures, safe in the trees rather than venture onto the ground?

I suspect developing civilization and high technology are two very different things. We can look at our own world to see that it was seasonal changes and northern latitudes that developed new technologies, mostly to combat the climate and resource scarcity.

There is no reason I can think of that arboreal monkeys or apes couldn't develop some form of higher intelligence and tribalism, but they certainly won't be splitting the atom due to the constraints of their environment.

Indeed!  I quite agree with you. Because we didn't develop that kind of technology when we were confined to tropical climates.  It's also one of the things that perhaps drove Neanderthals to extinction.  I remember reading that the last vestige of them lived near Gibraltar and froze to death there because they could not cross back over to the warm climate of Africa.

You're right about higher intelligence and tribalism being much easier, we see that in the great apes and other creatures like elephants and dolphins too.

It's interesting that they'd still have tails- perhaps those would go away with time also or were they needed for balance?

No, those would remain, as they do not impede the development of intelligence. As we have already seen - intelligence does not "require" an upright posture - just a freedom to manipulate tools. Interestingly, the theropod dinosaurs were one of the few creatures on this planet that possess actual 'hands' as we have, along with primates.  

Indeed, and I wonder if sea creatures can also manipulate tools, like dolphins for example.  They dont have hands, but they have other ways of doing so, with their snouts, like elephants can with their trunks and some birds do with their bills or beaks.

like dolphins for example.  They dont have hands, but they have other ways of doing so, with their snouts, like elephants can with their trunks and some birds do with their bills or beaks.

Unfortunately for dolphins - they live in an environment that severely impedes their progress to higher technology, along with the lack of any manipulatory appendages (as you pointed out, flippers are flipping useless - elephantine noses are very dexterous and bills can be used in conjunction with claws or even wings). It is something of a natural tragedy - they have the intelligence and capacity for social dynamics and natural curiosity - but can't advance to any great technological level unless something drastic were to happen. perhaps we can be the crucible for this catalyst - we could "Uplift" them by modifying their flippers to be more useful. That is literally the only thing we'd need to do.


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I've read about uplifting it's really interesting!  Of course we should treat all animals well, lest we have a Planet of the Apes scenario one day (we should treat them well regardless).