Science questions not worth a thread I: I'm a moron!

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I see it now....they were making FTL neutrinos by beta decay of Na-22, to use FTL neutrinos as time travelling messengers (going back say 5 years) to accelerate their development of nuclear materials!

Spoiler :
But don't fire up the DeLorean just yet. Physicists are skeptical that the tiny subatomic particles, called neutrinos, really are breaking the cosmic rule that nothing goes faster than light. And even if they are, neutrinos don't make the best vessel for sending signals to the past because they pass through ordinary matter almost unaffected, interacting only weakly with the wider world. [Countdown of Bizarre Subatomic Particles]

So you may be able to send neutrinos back in time, but would anyone notice? "If you're trying to get people's attention by bouncing neutrinos off their head, you could wait for quite awhile," Seth Lloyd, a physicist at the Massachusetts Institute of Technology, told LiveScience.

That hasn't stopped physicists from imagining the possibilities in a world where faster-than-light travel is possible. If the neutrino experiment is confirmed, it opens the door to at least sending messages through time using those neutrinos, physicists say.

http://www.livescience.com/16207-faster-light-discovery-time-travel.html
 
Is it rational to think that all the laws of physics will always be the same?

(Not really my question; more like something that came out of a painfully inane discussion I had a couple days ago. It's the sort of thing that happens when philosophers with no training in science try to talk about science).
 
Is it rational to think that all the laws of physics will always be the same?

(Not really my question; more like something that came out of a painfully inane discussion I had a couple days ago. It's the sort of thing that happens when philosophers with no training in science try to talk about science).

Depends on how you define "laws of physics".

If you define it as the body of theories we have today, then it is not rational to expect them to stay the same. We know them to be incomplete and any extension might yield surprising elements that might change the laws of physics as we know them.

If you define it as the underlying set of rules of the universe that we might or might not discover one day, then you can always define them in such a way to be always the same. If there is some change, there just needs to be another law that explains that change. So in this case it is rational to think they are always the same, as this is by design.
 
I may be taking the question the wrong way, but even with the first definition, it's still rational in almost all situations to think that the laws of physics have not, in fact, changed, and draw conclusions based on your current understanding of those laws. E.g. if you leave a pizza in the fridge and the next day it's gone, it's rational to expect the laws of physics to have remained constant and assume that your flat-mate ate it, whereas it's irrational to think that the laws of physics have changed in such a way as to allow your pizza to open the fridge door and walk off. Or if you do an experiment that produces results that are contrary to our current understanding of physics, it's much more likely that your experiment (or your interpretation of the results) was flawed than that the laws of physics are wrong.

In other words, I think it is pretty much always irrational to conclude that the laws of physics are wrong; it is instead rational to find an explanation that conforms with the current laws of physics.
 
I'd say that being always the same is in the very definition of what a law of physics is. If it was not always true, it wouldn't be a law of physics.
 
In other words, I think it is pretty much always irrational to conclude that the laws of physics are wrong; it is instead rational to find an explanation that conforms with the current laws of physics.

I agree. However the "pretty much always" part is the tricky part. If an experiment disagrees with the theory, there is a very small, but nevertheless greater than zero, probability that (our current understanding of) a law of physics is wrong. And if this is the case, there is a high reward for discovering it. Usually, this is Nobel prize territory. So while it is certainly rational to try to understand the effect in terms of the current laws of physics, it would be irrational to entirely ignore the possibility that they might be wrong.

Of course, usually the working assumption has to be that the laws of physics as we know them are correct and disagreement with the theory is usually due to an error in either the experiment or the theoretical calculations. But if the evidence starts to pile up, you have to consider the possibility that the laws of physics as we know them are incorrect at one point.

For example, when the Quantum Hall Effect was discovered, they first thought their measurement device was broken. But when all replacement devices displayed the same thing, they had to publish that the behavior was totally different from the expected. And then they got a Nobel Prize for the discovery.

I'd say that being always the same is in the very definition of what a law of physics is. If it was not always true, it wouldn't be a law of physics.
That would be my second definition. Conceptually I fully agree, but in a practical sense it is useless, because we can never know whether what we call a law is always true or not.
 
Okay, yeah, so is this more accurate: it's always rational to assume that the laws of physics are correct to begin with, but it's sometimes rational to conclude that the current laws of physics are wrong, once all other explanations are exhausted.
 
Thanks guys. In fact, we were arguing about whether or not Hume was correct to say that it is irrational to think the sun will always rise. Personally, I don't interpret Hume in exactly that way, but I find it difficult to explain these things to some people. It's like sitting down to play chess with a person who believes that checkers is the only game in the world.
 
Why do adult cats still kneed, what's the adaptive value of that?

You'd only get speculation... domesticated animals retain weird traits for seemingly weird reasons. And then you have to contrast that with there not being much literature on what is and is not a trait in domestic animals vs their wild counterparts. Do adult wild cats knead? I'm unsure!

However, and freely admitting here it's speculation, but I'd guess it was neoteny where animals retain juvenile traits into adulthood. I've often heard it claimed adult domestic cats act like kittens and by keeping them around, we allow / encourage this. After all who doesn't like a good cat video on youtube?

If kneading was kept as adults in wild cats, I would assume it's something like stretching or trampling grass. With my cats, they always do it before sleeping.
 
Okay, yeah, so is this more accurate: it's always rational to assume that the laws of physics are correct to begin with, but it's sometimes rational to conclude that the current laws of physics are wrong, once all other explanations are exhausted.

That is not a rational assumption. Our laws of physics are wrong.

More specifically - Quantum mechanics and relativity contradict each other in certain ways. If you want to model what happens inside a black hole, for example, you need to use equations from both models. When you try to do that, you get nonsensical results (things like "probability = infinity").

I think of it as being similar to how Newton's Laws of Motion are wrong; they can be used to describe the behavior of objects in a limited set of conditions, so they look correct for a lot of experiments we can do here on Earth, but they fall apart when you get outside those conditions (e.g. clock desynchronization on GPS satellites if they're programmed using Newton's Laws).
 
Of course it's a rational assumption. Before we knew that certain things couldn't be predicted by Newton's Laws, it was rational to assume that they could. Otherwise you wouldn't get anywhere. The conclusion, that you can't predict it with Newton's laws, and so some new physics is needed, was also rational. What about that process - which is, in essence, the scientific method - is irrational?
 
What about that process - which is, in essence, the scientific method - is irrational?

Funny. The person I had the aforementioned conversation with was also trying to tell me that the scientific method is irrational. I'm still about as dumbfounded as you are. I really hate when people try to pull this false equivalence crap between science and religion/philosophy.
 
Funny. The person I had the aforementioned conversation with was also trying to tell me that the scientific method is irrational. I'm still about as dumbfounded as you are. I really hate when people try to pull this false equivalence crap between science and religion/philosophy.

Let's pretend it is irrational for a moment... does that change anything? Science works. Other methods do not. If you want to argue science is irrational, fine, there's still no better / less irrational way of understanding the universe.

I've yet to see a rocket launched into orbit by divination. I've yet to see prayer power a country.
 
That is not a rational assumption. Our laws of physics are wrong.

More specifically - Quantum mechanics and relativity contradict each other in certain ways. If you want to model what happens inside a black hole, for example, you need to use equations from both models. When you try to do that, you get nonsensical results (things like "probability = infinity").

I think of it as being similar to how Newton's Laws of Motion are wrong; they can be used to describe the behavior of objects in a limited set of conditions, so they look correct for a lot of experiments we can do here on Earth, but they fall apart when you get outside those conditions (e.g. clock desynchronization on GPS satellites if they're programmed using Newton's Laws).
What you're saying doesn't mean that our physical theories are wrong, just that they're incomplete. In physics we use models that include abstractions - even in dimensions where, say, Newtonian physics holds true (i.e. within resting reference frames), we don't calculate the behavior of every atom of an object, we consider the abstracted objects themselves. This is called an effective model. When an effective model is applicable, i.e. going to produce correct results, is usually included in its formulation. So it's not wrong in that regard: it can do everything it claims. It's just not applicable everywhere.

In a similar vein, general relativity and quantum physics are effective models of the world we live in. On the other hand, we don't even know for sure if a universal theory or model for the entire world is even possible.

Theories that are "wrong" in your words may be all we'll ever have.
 
... On the other hand, we don't even know for sure if a universal theory or model for the entire world is even possible.

Or, even if possible, whether it would be useful for anything.

It might give us exact equations for solving any conceivable situation... but the equations themselves might be too complex for us to solve.
 
I guess the main drive behind it is to resolve situations Elephantium already alluded to: where both general relativity and quantum physics ought to apply, but contradict each other, i.e. quantum gravitation. The most interesting case there is probably the very early universe that had only a quantum scale size.

Another point is definitely the popular notion that different models for different situations seems to be an artificial approach chosen out of necessity, that can be circumvented if one looks "deeper". There isn't really anything that says this must be the case. After all, the idea of using models itself is an artificial approach chosen out of necessity.
 
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