You find yourself in the cretaceous

[DBT]

Around one in a million for deaths due to sharks in Australia in 1965; About one in fifty million for crocodiles.

I'll take those odds.

Most people are not in that environment. Those who are, most likely swim in a public beach that has shark nets and lifeguards to keep watch. It's somewhat of a tamed environment.

 

[Politesse]

It depends on where you are....if you choose to swim in a Croc infested river or creek, your chances of being taken are quite high.

The OP only secified a continent, and a significantly larger one. So how likely, droppped at some random point in Oceania, are you to be eaten by a crocodile or shark?

The OP is related to conditions in the Cretaceous and the likelihood of attack in that environment. Which may, I guess, be comparable to the wilds of Africa before human technology came into the picture. Would you not consider the possibility of Lion attack, for instance?

Wrong. I mean, who knows about lions necessarily, but unlike in the Cretaceous, we did have other known predators in African pleistocene, well-familiar with hominids and clearly in the habit of taking and eating them. So if you're talking about the number of predator attacks exclusively, Africa would be a MUCH more dangerous place for us, as it was for our ancestors:


The Taung child, taken and eaten by a bird of prey 2.8 million years ago.

On the other hand, in some other ways our species' homeland would be considerably less dangerous for us than most places in the Cretaceous, at least if we are talking about the trree-filled lowlands we evolved in; we are naturally adapted to the ancient African climate, so less fear of exposure to the elements or unknown diseases/micro-organisms, a much more worrying prospect with respect to the Cretaceous, if you ask me.

 

[skepticalbip]

Around one in a million for deaths due to sharks in Australia in 1965; About one in fifty million for crocodiles.

I'll take those odds.

Most people are not in that environment. Those who are, most likely swim in a public beach that has shark nets and lifeguards to keep watch. It's somewhat of a tamed environment.

That was my thought too. Such statistics, if one in a million, is counting all Australians in that million then they would be rather meaningless. A more meaningful statistic would be the percentage of surfers attacked by sharks without including all the Australians that never get in the water. That second statistic would better inform someone interested in taking up surfing.

 

[DBT]

Re, Politesse, the point is that environments where large predators are active hold the risk of an attack. So if one is going to spend time in such an environment, taking precautions, some means of stopping, deterring or repelling an attack may be a good idea. A gun not only makes noise, but is capable of stopping a predator in its tracks.

 

[bilby]

Most people are not in that environment. Those who are, most likely swim in a public beach that has shark nets and lifeguards to keep watch. It's somewhat of a tamed environment.

That was my thought too. Such statistics, if one in a million, is counting all Australians in that million then they would be rather meaningless. A more meaningful statistic would be the percentage of surfers attacked by sharks without including all the Australians that never get in the water. That second statistic would better inform someone interested in taking up surfing.

Certainly few of the citizens of Alice Springs are at such a high risk of shark attack.

 

[skepticalbip]

Most people are not in that environment. Those who are, most likely swim in a public beach that has shark nets and lifeguards to keep watch. It's somewhat of a tamed environment.

That was my thought too. Such statistics, if one in a million, is counting all Australians in that million then they would be rather meaningless. A more meaningful statistic would be the percentage of surfers attacked by sharks without including all the Australians that never get in the water. That second statistic would better inform someone interested in taking up surfing.

Certainly few of the citizens of Alice Springs are at such a high risk of shark attack.

But, if the statistics are taken seriously, they have a one in a million chance of shark attack, same as the surfers riding the curls at Byron Bay.
... damned land sharks...

 

[DBT]

Statistics and damn statistics...

 

[Angra Mainyu]

Take for example time travel in the universes we create: if I create a universe of Dwarf Fortress a d decide to go back in time, it's really not something that can be done from inside, but I can load into an earlier save file. If I change something there, it's not even the same string of execution anymore. It's a divergent file instead.

Sure, that'a a parallel universe. I considered that one. No risk for our universe, either.

The assumptions AM makes on time travel paradox rely on tacit assumptions AM makes about the cosmology of whatever system this time travel is happening in, assumptions that are quite probably very bad.

But those are not assumptions I make. Those are assumptions that you attribute to me, even though i clearly considered the alternative of a parallel universe.

In such a cosmology, there would be no paradox.

Obviously. And also as I pointed out, humanity does not blip out of existence, either. Killing a T-Rex remains unproblematic for humans.

 

[Angra Mainyu]

We probably would not appear to be like their typical prey, but is a dinosaur all that discerning? We are not the usual prey of sharks or crocodiles, etc, but that doesn't stop them from attacking humans who are in the wrong place at the wrong time.

Actually, sharks generally don't think too much of us. That's why many people survive shark attacks--the shark bites and decides it doesn't like the meal.

Alligators/crocodiles are not selective, they'll try to eat anything that's not too big.

Is there anything that crocodiles see as too big? They do take gnus... it is just a matter of ripping off parts small enough to swallow after they drown the gnu.

Sure, adult hippos are too big. Crocodiles do not go for that.

 

[Angra Mainyu]

I don't see why it is logically impossible to displace yourself in time any more so than it is to displace yourself geographically. My position and its effects on the world are fairly consistent whether I'm performing them at t1 or t2. If I can manage to transport myself to t2 from t1, it doesn't create a "paradox", I'm just now affecting things from that standpoint. Are you guys appealing to some sense of "fate" or "destiny"? I don't see why the future couldn't be altered. We know that the future can be altered. We do this all the time. We just usually can't see the effects of our actions until they transpire.

No, it's not about destiny. But suppose that you go from t2 back to t1, centuries earlier. So, at t2, you exist. At t1, you begin to pass on viruses that people at t1 have never encountered. One of your ancestors dies as a baby. Then you are never born. But how come you exist at t1? Two ways of looking at this that are consistent:

1. Parallel universes. You exist in your universe of origin at t1. The other one is different, and there is no counterpart of you in that one. The baby who died wasn't really your ancestor, but a counterpart of some sort in the parallel universe.

2. By going back to t1, you already destroyed the universe at any later time. So, there is no you at t2 (this is kind of a parallel universe scenario, but more destructive).


Are there other ways?
Yes, but either they do not affect the present, or they are very, very weird. And even in the weird ones, there is a problem that it's already happening, so the present gets destroyed from the past anyway.

I mean, suppose you go back to t1. Your very presence there changes the future, and somehow the changes propagate forward. Do you still get born? Even tiny differences can snowball. But in any case, with billions of years yet to come, other time travelers will go back and mess the time line so many times over that you get out of existence anyway. And I have yet to see a consistent model of that, which also is in line with our observations and does not result in some kind of global skepticism like the universe as we know it existed for a minute or a year or something like that.

 

[Treedbear]

I don't see why it is logically impossible to displace yourself in time any more so than it is to displace yourself geographically. ...

...
Are there other ways?
Yes, but either they do not affect the present, or they are very, very weird. And even in the weird ones, there is a problem that it's already happening, so the present gets destroyed from the past anyway.
...

When we talk about displacing something in time and/or in space it typically means there is still a continuity maintained between the two points that must be traversed. It's impossible to change positions in three dimensions without doing so. It would be impossible to do so in the 4th dimension of time for the same reason. Space and time are interdependent. You can't move through space without also moving through time, and when two objects with identical space-time trajectories accelerate away from each other in space they also do so in time. To just go back in time would disassociate you from all coordinates in space. That becomes a big problem if you're orbiting around a star and that star is itself moving at some velocity. Just as there is no absolute reference in space there is none in time. That is, unless there is a relative continuity maintained. You might imagine going back to the Cretaceous would necessarily mean also displacing your position to exactly where you would be on Earth at exactly the same location in its orbit around the Sun that was also displaced by however many parsecs across the galaxy that is who-knows-where in the universe. None of it makes any sense. If you could find enough energy to run everything backwards perhaps, but by doing so history would be erased at the same time.

 

[DBT]

Perhaps gravity keep the time traveler bound to the earth as they tunnel back in their space/time fold?

 

[untermensche]

I don't see why it is logically impossible to displace yourself in time any more so than it is to displace yourself geographically. ...

...
Are there other ways?
Yes, but either they do not affect the present, or they are very, very weird. And even in the weird ones, there is a problem that it's already happening, so the present gets destroyed from the past anyway.
...

When we talk about displacing something in time and/or in space it typically means there is still a continuity maintained between the two points that must be traversed. It's impossible to change positions in three dimensions without doing so. It would be impossible to do so in the 4th dimension of time for the same reason. Space and time are interdependent. You can't move through space without also moving through time, and when two objects with identical space-time trajectories accelerate away from each other in space they also do so in time. To just go back in time would disassociate you from all coordinates in space. That becomes a big problem if you're orbiting around a star and that star is itself moving at some velocity. Just as there is no absolute reference in space there is none in time. That is, unless there is a relative continuity maintained. You might imagine going back to the Cretaceous would necessarily mean also displacing your position to exactly where you would be on Earth at exactly the same location in its orbit around the Sun that was also displaced by however many parsecs across the galaxy that is who-knows-where in the universe. None of it makes any sense. If you could find enough energy to run everything backwards perhaps, but by doing so history would be erased at the same time.

In the past all the matter that makes up YOU, your body, already existed. The matter that makes up your body has existed for billions of years.

If you take the matter that is your body and go back in time that matter is already there, scattered in many different places.

So to go back in time, unless all the matter that later makes up your body instantly disappears, is to create matter.

An impossibility.

 

[DrZoidberg]

You can bring some things with you. No tank. But some small arms, AR -15 or so. Maybe some other things. How would you survive. We’ll make it North America so you have to deal with T. rex.

Large mammals didn't exist back then. I doubt T Rex would have identified humans as food.

I think I'd bring camping gear and a stack of pornos. It's going to get mighty lonely there. Non-petrol powered farming equipment and manuals for it, would also be good. A selection is seeds. Especially potatoes.

 

[Politesse]

I don't see why it is logically impossible to displace yourself in time any more so than it is to displace yourself geographically. My position and its effects on the world are fairly consistent whether I'm performing them at t1 or t2. If I can manage to transport myself to t2 from t1, it doesn't create a "paradox", I'm just now affecting things from that standpoint. Are you guys appealing to some sense of "fate" or "destiny"? I don't see why the future couldn't be altered. We know that the future can be altered. We do this all the time. We just usually can't see the effects of our actions until they transpire.

No, it's not about destiny. But suppose that you go from t2 back to t1, centuries earlier. So, at t2, you exist. At t1, you begin to pass on viruses that people at t1 have never encountered. One of your ancestors dies as a baby. Then you are never born. But how come you exist at t1? Two ways of looking at this that are consistent:

1. Parallel universes. You exist in your universe of origin at t1. The other one is different, and there is no counterpart of you in that one. The baby who died wasn't really your ancestor, but a counterpart of some sort in the parallel universe.

2. By going back to t1, you already destroyed the universe at any later time. So, there is no you at t2 (this is kind of a parallel universe scenario, but more destructive).


Are there other ways?
Yes, but either they do not affect the present, or they are very, very weird. And even in the weird ones, there is a problem that it's already happening, so the present gets destroyed from the past anyway.

I mean, suppose you go back to t1. Your very presence there changes the future, and somehow the changes propagate forward. Do you still get born? Even tiny differences can snowball. But in any case, with billions of years yet to come, other time travelers will go back and mess the time line so many times over that you get out of existence anyway. And I have yet to see a consistent model of that, which also is in line with our observations and does not result in some kind of global skepticism like the universe as we know it existed for a minute or a year or something like that.

I am still there in t1. This isn't the movies. But were I to return to t2, it might look different than I expect. It would be complicated to consider a "present" that is in constant flux due to time traveler intervention, but the world is pretty damn complicated and weird in the first place, if you're trying to model how it works, as you say.

 

[Politesse]

When we talk about displacing something in time and/or in space it typically means there is still a continuity maintained between the two points that must be traversed. It's impossible to change positions in three dimensions without doing so. It would be impossible to do so in the 4th dimension of time for the same reason. Space and time are interdependent. You can't move through space without also moving through time, and when two objects with identical space-time trajectories accelerate away from each other in space they also do so in time. To just go back in time would disassociate you from all coordinates in space. That becomes a big problem if you're orbiting around a star and that star is itself moving at some velocity. Just as there is no absolute reference in space there is none in time. That is, unless there is a relative continuity maintained. You might imagine going back to the Cretaceous would necessarily mean also displacing your position to exactly where you would be on Earth at exactly the same location in its orbit around the Sun that was also displaced by however many parsecs across the galaxy that is who-knows-where in the universe. None of it makes any sense. If you could find enough energy to run everything backwards perhaps, but by doing so history would be erased at the same time.

In the past all the matter that makes up YOU, your body, already existed. The matter that makes up your body has existed for billions of years.

If you take the matter that is your body and go back in time that matter is already there, scattered in many different places.

So to go back in time, unless all the matter that later makes up your body instantly disappears, is to create matter.

An impossibility.

It is also possible to transport matter. If you are doing so across dimension t rather than dimension x/y, why would that be impossible? The universe doesn't follow laws, we model laws from our observations of its normal behavior. If we started messing with one of the laws via a device of some kind, the universe won't be offended.

 

[untermensche]

When we talk about displacing something in time and/or in space it typically means there is still a continuity maintained between the two points that must be traversed. It's impossible to change positions in three dimensions without doing so. It would be impossible to do so in the 4th dimension of time for the same reason. Space and time are interdependent. You can't move through space without also moving through time, and when two objects with identical space-time trajectories accelerate away from each other in space they also do so in time. To just go back in time would disassociate you from all coordinates in space. That becomes a big problem if you're orbiting around a star and that star is itself moving at some velocity. Just as there is no absolute reference in space there is none in time. That is, unless there is a relative continuity maintained. You might imagine going back to the Cretaceous would necessarily mean also displacing your position to exactly where you would be on Earth at exactly the same location in its orbit around the Sun that was also displaced by however many parsecs across the galaxy that is who-knows-where in the universe. None of it makes any sense. If you could find enough energy to run everything backwards perhaps, but by doing so history would be erased at the same time.

In the past all the matter that makes up YOU, your body, already existed. The matter that makes up your body has existed for billions of years.

If you take the matter that is your body and go back in time that matter is already there, scattered in many different places.

So to go back in time, unless all the matter that later makes up your body instantly disappears, is to create matter.

An impossibility.

It is also possible to transport matter. If you are doing so across dimension t rather than dimension x/y, why would that be impossible? The universe doesn't follow laws, we model laws from our observations of its normal behavior. If we started messing with one of the laws via a device of some kind, the universe won't be offended.

If I arrive in the past all the matter that makes up my body is already there. But it is not making up my body yet. It is scattered who knows where all over the place.

If I go back in time that is equivalent to creating matter. It is not just moving in a dimension like moving through space.

 

[bilby]

It is also possible to transport matter. If you are doing so across dimension t rather than dimension x/y, why would that be impossible? The universe doesn't follow laws, we model laws from our observations of its normal behavior. If we started messing with one of the laws via a device of some kind, the universe won't be offended.

If I arrive in the past all the matter that makes up my body is already there. But it is not making up my body yet. It is scattered who knows where all over the place.

If I go back in time that is equivalent to creating matter. It is not just moving in a dimension like moving through space.

Creating matter isn't difficult. It happens all the time - at CERN, humans do it regularly.

It needs a lot of energy, but nobody suggested that time travel would be cheap.

And if you are right, then the departing traveller's matter is destroyed - so there's your source of at least some of the necessary energy.

 

[skepticalbip]

... snip ...

And if you are right, then the departing traveller's matter is destroyed - so there's your source of at least some of the necessary energy.

There containment of that energy being only a minor technical concern to be worked out..

 

[untermensche]

It is also possible to transport matter. If you are doing so across dimension t rather than dimension x/y, why would that be impossible? The universe doesn't follow laws, we model laws from our observations of its normal behavior. If we started messing with one of the laws via a device of some kind, the universe won't be offended.

If I arrive in the past all the matter that makes up my body is already there. But it is not making up my body yet. It is scattered who knows where all over the place.

If I go back in time that is equivalent to creating matter. It is not just moving in a dimension like moving through space.

Creating matter isn't difficult. It happens all the time - at CERN, humans do it regularly.

It needs a lot of energy, but nobody suggested that time travel would be cheap.

And if you are right, then the departing traveller's matter is destroyed - so there's your source of at least some of the necessary energy.

Matter is not created by breaking up existing matter.

Matter that makes up me in the past is scattered all over the place.

Somehow all that matter needs to be created new without injuring me.

Time travel is an utterly ridiculous irrational hypothesis that is not possible.

It is fantasy, not science.