If anybody wants to argue that America is doomed as a civilization, I no longer have the strength or will to oppose them.
Sure, unless there are good reasons to think otherwise. We have good reason to assume the sun will rise tomorrow, but good reasons to think it won’t 5 billion years from now.
I think the responses have shown that the assumption has not been pulled out of our collective asses. If the laws haven’t changed for over 10 billion years, it’s reasonable to assume they won’t change tomorrow. Anyone can doubt anything, but for it to be a reasonable doubt we need a bit more.
Of course it hasn’t been pulled out of anyone’s ass. It’s a very common assumption. The OP is expressing doubt over it nonetheless. You don’t consider it to be a reasonable doubt; very well, then. Most wouldn’t. All the same, the OP is expressing it. In order to dissuade him from doing so, could you demonstrate why it isn’t a reasonable doubt, without simply appealing to the very principle being doubted? That’s the sort of thing which would be useful to the skeptic.
We already know that physical principles will change under extreme configurations. No one can really say what goes on in the center of a Black Hole for instance as all our “laws” of nature cease to produce meaningful answers in such a place.
Indeed we see this with Inflation Theory where the Universe experienced exponential expansion for a very short moment post Big Bang. Something about that configuration of the universe allowed for markedly different behavior than we see today.
Most of what we have today are more like owners manuals of how the Universe operates rather than fundamental descriptions. For instance Newton’s Theory of Gravity does a great job of predicting how gravity works in most cases but it never said what gravity actually is. Einstein answered that and improved on the accuracy of the behavior of gravity.
So we get ever more refined theories but while they may provide useful and accurate frameworks for making predictions they can still be wrong. The Ptolemaic system, for example, assumed a heliocentric universe but it worked. You could make fairly good predictions with it. It was cumbersome but it worked till some thousand years later someone found a more elegant framework that made better predictions.
I think the search for a Theory of Everything (TOE) is the search for not the owners manual but a search for WHY everything is the way it is. That there is no more question about “why” it works that way. Presumably this would put to rest the idea that a physical principle that works today would not work tomorrow. It works because it HAS to work that way. Some think String Theory (or M-Theory if you prefer) is on that road. For instance it is the first theory to predict gravity. It is built in…if you knew nothing of gravity and looked at M-Theory gravity is an undeniable result.
So we keep looking and in the meantime hope things that work today will continue to work tomorrow (probably a good bet).
Right. You can’t justify induction by induction. That’s cheatin’. 
OTOH, few scientists worry about it. It’s a problem for philosophers of science. And nobody is suggesting we stop doing science simply because there is a philosophical problem with induction. Various philosphers of science have proposed descriptions of science that don’t include induction, but they pretty much try to describe science as it is done, and the descriptions have usually included inductions that were either called another name or simply not mentioned.
By the way, this audiobook covers the issue admirably: The Great Courses
You mean geocentric.
Well, here’s the thing.
As others have pointed out, it seems as though the laws of physics haven’t changed in the past, and therefore we have no good reason to believe they will change in the future.
Of course, that doesn’t mean they won’t change in the future, in which case our current understanding of physical law will be changed to a special case of some future, more inclusive theory of physical law. Or, we’ll all be dead, because those changes in the laws of physics make the formation of atoms impossible, and we’ll all dissolve into quarks. It could happen tomorrow.
But we don’t expect it to happen tomorrow, because we’ve had several billion years where it didn’t happen tomorrow. Why should tomorrow be any different than yesterday? Of course it could be different, but we have no good reason to imagine it will be different.
This reminds me of SM Stirling’s “Dies the Fire” novels, where suddenly the laws of physics seem to change and electricity and gunpowder and steam engines and so forth don’t work any more, and most of humanity dies. And experiments carried out by the survivors indicate that the laws of physics have indeed changed, at least on Earth, in strange and subtle ways. Why couldn’t this really happen tomorrow? Well, it could, except there’s no reason to believe it will.
Another way of asking this question is to wonder why we bother trying to figure out the laws of physics in the first place. Why do we human beings want to do such a thing? Well, human beings are animals that evolved through a process of natural selection, and one of our adaptations is that we have a large brain that is capable of predicting the future. Animals that successfully predict the future survive and reproduce, animals that fail to predict the future die and fail to reproduce.
And so we don’t expect our brains to be perfect future-predicting machines, rather they are imperfect machines that only predict the future at a rate better than chance. Our formulations of the laws of physics are provided by the limited and imperfect brains of physicists. But our understanding of those laws enable us to do things that we couldn’t do if we refused to trust our understanding of those laws.
If I fire a gun at my enemy’s head, my understanding of the laws of physics enable me to predict that he will be killed. If my enemy remains agnostic about the laws of physics, and refuses to speculate that they will remain constant in the future, he’s going to get a bullet in the brain, and he’s going to be dead. Physicists theorized that you could release a lot of energy through the disintegration of the atomic nucleus, and lo and behold they were right, and two cities vanished off the face of the earth.
And so on. So we can’t entirely discount the possibility that tomorrow we’ll all dissolve into a soup of quarks, how are we supposed to react to that possibility? It seems to me that the way we should react is to acknowledge that possibility, yet realize that there’s no point in worrying about it unless it happens, and also realize that we have absolutely no good reason to believe it will happen.
He’s only going to be dead if your understanding of scientific law continues to hold true as you fire the gun. To use this as a justification for believing in the constancy of scientific law is begging the question.
Yep, believing in the constancy of scientific law has led to a lot of successes in the past. Now, why should we believe it will continue to lead to successes in the future? Most of us do, of course, but when confronted with one who does not do so right off the bat, what can we say that has some strength in removing his doubts?
The laws of physics will work just fine tomorrow. However, don’t expect the laws of quantum physics or general relativity to work Friday night, or Saturday during the day. As Hitler pointed out, that’s “Jewish physics,” and Yom Kippur starts this Friday at sundown. So in observance of the holy day, they won’t work.
I don’t see how we appealed to the principle being doubted. The justification for reasonableness, which is weaker than that for any kind of proof, is that if you went back in time and predicted the laws of physics would be the same tomorrow as today, you would have been right. In fact those of us who said this a few days ago were right also. That’s about all the evidence anyone is likely to get. Reasonable people might disagree on what is reasonable, and the OP seems reasonable, so I’m willing to wait a reasonable time for a reasonable response to the reasonable question.
One approach might be to ask if the laws are different from those things that we don’t expect to be invariant. I wouldn’t want to bet that hemlines are the same next year as this. So, we can try to identify characteristics of those things which seem to be invariant and those things which don’t, and see if that makes sense. It certainly doesn’t prove anything, but it is another reason to believe.
If we only knew that the speed of light is what it is in the last 50 years or so, then it would be very reasonable to think that maybe it’s been varying all along and we just think it’s constant in our snapshot of time that we’ve been making accurate measurements.
For those people wondering just that, then I think it will help lower their doubt to point out that c has been constant for 10 billion years or so.
The fact that c has been constant the whole time does make it harder to imagine what could cause it to change in the future, so should convince most people who have doubted the constant-c assumption.
On the other hand, as you point out, it is not proof of future constancy, but science doesn’t deal in proofs.
Well, that’s the point.
We try to predict the future, and the the extent that we’re able to do so, we survive and prosper. To the extent that we’re unable to do so, we fail and die.
If I fire a gun at my enemy’s head, I have a justified belief that the laws of physics won’t change in time to prevent my enemy’s brain from being blown all over the wall.
Every day we human beings make choices that are literally equivalent to betting our lives that the laws of physics will hold true. You eat a sandwich, confident that the sandwich won’t disolve into quarks. You walk down the street, confident that electrons will continue to repel each other and the street will remain solid. You go out of the house confident that gravity won’t reverse and you won’t fall into the sky.
And we are obligated to bet our lives in the manner every minute of every day. The only alternative is suicide. Thing is, people can and do commit suicide every day, and if they prefer oblivion to continuing to live in such an uncertain world, how can I stop them? The only problem is that our world of living human beings must be composed exclusively of people who prefer to be alive, since the people who prefer to be dead are already dead. And people who prefer to be dead tend not to reproduce, and thus the next generation of children tend to prefer to be alive as well. We have no good reason to prefer to be alive, it’s just that it is the nature of living animals to prefer to be alive, otherwise they’re dead. Even understanding WHY I want to live and reproduce and have a family and love my wife and kids and understanding that there’s no cosmic justification for it all, doesn’t change the fact that I DO want to live and love my kids and such.
My dismissal of your argument is similar to my dismissal of solipsism, rejection of logic, and other such arguments. The problem is not that they must be wrong, the problem is that they are sterile arguments. If you really believed you were a brain in a jar hallucinating the rest of us, what exactly do you think you’re doing arguing with us and telling us that we don’t exist? If you don’t believe in logic or reason, how can you convince other people that you’re correct? You can’t use logic to give people a reason to reject logic.
So your worry that we can’t expect the laws of physics to stay constant in the future just because they’ve stayed constant in the past can be rejected on similar grounds. We have no reason to expect it to happen. If you provided some reason to believe it…some evidence that the laws of physics are not constant, then we could talk about it usefully. But arguing that just because the sun came up yesterday that doesn’t mean it’s going to come up tomorrow is about as useless as arguing that you’re a brain in a jar. Suppose we accept it as true? Then what? OK, we accept it as true, then we’re obliged to dismiss it and go about our business as if it weren’t true, because that’s the only way we know how to survive. Maybe one day our belief will prove to be unjustified, and our dependence on our current understanding of the laws of physics will prove to be wrong, and we’ll all die because of it.
Sure, it’s useful to examine whether the laws of physics really are invariant, whether they varied in the past, whether they vary in other places, or whether they vary under certain conditions. This is how breakthroughs like relativity get discovered, when we find that physical laws such as f=ma don’t hold under certain conditions, and f=ma is only a special case of a broader physical law. But every day you literally bet your life that f=ma for the conditions you find yourself in, when you put on a hat and don’t worry that the hat will crush your head, when you stand up and don’t worry that your leg muscles will propel you through the roof of your house.
Yes.
I really don’t know why this General Question with a yes or no answer is even in Great Debates.
Sure, the simple answer is that as far as we can tell, the laws of physics haven’t changed since the formation of the universe, and so we have no reason to suspect that they will change in the future. But the question isn’t just whether the laws of physics are constant, but whether we are justified in our belief that the laws of physics are constant.
And you can’t really answer that question without getting into woo-woo topics like epistemology and philosophy of science.
Of course, arguing with somebody who pretends not to believe in logic is useless, since if they really believed that they wouldn’t be arguing with you. But in my experience people who claim they don’t believe in logic really do, because they are willing to eat a ham sandwich in the belief that the ham sandwich will nourish them rather than kill them, they get out of the way of moving vehicles, and so forth.
I hope no one thinks I don’t believe in logic, whatever that would mean. I have merely tried to point out what would have persuasive force to the hypothetical inductive skeptic and what would completely fail to (on grounds of circularity). And if it should turn out that nothing at all should have persuasive force to him, that there is no argument rationally moving him from his starting premises alone closer to our own confidence in induction, then so be it; he shall live on an inductive skeptic and we shall live on inductive believers, and that will be that. All explanations must come to an end somewhere; it may well be the case that our use of induction is primitive and fundamental, independent from, and therefore not justified by, our other basic reasoning principles, but none the worse for it.
I just don’t want anyone to mistakenly think that a circular “justification” for inductive logic does much anything.
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I’m not sure how one believes in logic. Can you believe in math?
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Logical empiricists didn’t contest the problem of induction, they tried to come up with work-arounds, like the hypothetico-deductive model.
http://www.anselm.edu/homepage/dbanach/logemp.htm
http://www.anselm.edu/homepage/dbanach/logemp.htm
If they had a fault, it was too strong a “belief” in logic, not mock disbelief.
One of these days I’m going to ask you guys to explain the value of philosophy to me because it seems like a complete waste of brainpower–and maybe YOU (collectively) have brainpower to waste but I (obviously) don’t. Perhaps concluding that all ravens are black because I’ve never seen one that was not black is questionable, but discussing whether there is anything but a vanishingly small chance that the laws of physics won’t work the same tomorrow as they apparently have for the past 547,000,000,000 yesterdays seems to me to be a silly waste of time. Maybe they won’t, but it is definitely how you should place your bets.
Science and the philosophy of science answer different questions. Science tries to use the most practical and reliable methods to predict, control, and explain natural phenomena. It’s quite important to know at what temperature water boils. The fact that the answer is probabilistic or qualified doesn’t hurt the science part of the answer. Nor does the fact that we can’t logically prove that the boiling point won’t be very different tomorrow make the enterprise less scientific. Philosophy of science answers more esoteric questions like “What is science?” “How is science different from religion or metaphysics?” and “How does science work?” Distinguishing between science and religion became importan recently with the popularity of intelligent design. You can’t scientifically prove a theory isn’t scientific–that’s a matter of definition and philosophy.
And you’ve got to look at the answers in context. Popper and Kuhn responded to very specific problems posed by earlier writers. Popper in particular tried to deal with the problem of induction (by avoiding it). Whether he did so successfully is debatable, but he was responding to a problem that’s haunted those who try to describe scientific reasoning and the scientific method for a long time. If you don’t understand his theory as a response, it’s kind of tough to understand why he thought it was important to avoid the issue. Simply answering “yes, next question,” while amusing, isn’t an especially useful contribution to that debate.
On the other hand, if we want to form useful conclusions about the world, we have to use something. And science usually gets the right answer eventually. So we rely on scientists to settle questions about the world, even if we can’t know absolutely for sure their answers might not be correct forever. It’s close enough, or it’s as close as we can get, anyway. But when we start thinking about what science is really about, we are reminded that there are some unprovable assumptions, at least if we want proof in terms of formal logic.