Does cosmology have the answers?

[Dadface]

Armed with a mass of observations and mathematical equations cosmologists tell us that the universe started with a big bang and that its ultimate fate is,as yet,unknown.Fair enough but now the ordinary person in the street is starting to believe the big bang theory and that we will soon have a theory of everything, many blindly accepting this because they are told it is so.
Do the cosmologists,physicists and mathematicians who put this information into the public domain really believe that they have the absolute immutable truth or do some of them, occasionally,suffer from niggling doubts?
The big bang theory and every other theory we have are just that ,theories only and not necessarily truths and shouldn't this message,also, be passed more effectively into the public domain?

 

[HallsofIvy]

Of course. And what's really terrible is that the government hasn't warned people that the "theory of gravity" is onlythat and they might start floating off the planet at any moment!

I think the difficulty here is with your interpretaton of the word "theory".

I can't imagine anyone thinking that cosmology has "all the answers". It hasn't even asked all the questions!

 

[Fredrik]

I suggest that this thread be moved to the philosophy forum. The OP's questions and misunderstandings have little to do with physics.

Dadface, you don't seem to understand how the word "theory" is used by physicists. They wouldn't ever use the phrase "just a theory" except as a joke. A theory is a set of statements that can be used to predict the results of experiments. "The Earth is flat" and "The Earth is spherical" are both theories. It doesn't make sense to think of some theories as "true" and some as "false". They are all "false", but some theories are better than others, in the sense that they do a better job of predicting the results of experiments. Some theories are really good (e.g. general relativity), and some are really bad (the Earth is flat), but none of the theories that have been discovered so far make predictions that agree exactly with experiments. (That's why I said they're all "false").

It's also important to understand that experiments can only tell us is how accurately the predictions of the theory agree with the results of experiments. The only "facts" in science are statements of the form "Prediction A of theory B agrees with experiment C with accuracy D".

When you understand the above, you will understand why the phrase "just a theory" is so silly. There's no higher form of understanding than the kind you get by finding a theory and determining the accuracy with which it predicts the results of experiments. A theory doesn't stop being a theory at some point when there's sufficient evidence to support it.

One thing that isn't emphasized often enough about "the big bang theory" is that it's not really a theory. It's a set of predictions made by a theory. The theory is general relativity. We could be more specific and say that the relevant theory here is the assumption (supported by the observed large-scale homogeneity and isotropy of the universe) that the large-scale behavior of our universe can be described approximately by an exactly homogeneous and isotropic solution of Einstein's equation. Either way, the big bang should still be thought of as a set of predictions about the behavior of the universe at times in the past, present and future.

We obviously can't test the predictions about the past directly (since we can't go back in time), but we can certainly test the accuracy of the predictions about the present. We can also indirectly test the predictions about the past. For example, if the universe was extremely hot and dense in the past, getting hotter and denser the further back we look, then there must have been a time when atoms couldn't exist for very long (because they kept getting smashed to pieces by high-energy collisions). At some point, the universe must have expanded and cooled to the point where atoms could remain intact, and at that time the universe must have become transparent to light. (When free electrons got tied up in atoms, they couldn't stop light as effectively as before). If that's what happened, then this light should still be flying around all over the place, and guess what, it is. See e.g. the Wikipedia article on WMAP.

 

[Dadface]

Frederick I have no misunderstandings at all regarding the thread I started and I am using the word theory as it is understood by the lay person and not the physicist.If you think this thread has nothing to do with physics then what else is it about?Why don't you read my question properly?

 

[Fredrik]

You're asking if physicists believe that a specific theory is the absolute truth or if they have doubts. I don't see why you would ask that if you understand that a theory is never the absolute truth.

 

[atyy]

"...the very early universe is not yet directly accessible to our instruments ... Any theory framed in a homogeneous, isotropic model must be treated cautiously. ... inhomogeneous models, but this is a very active field of research today." Schutz, http://books.google.com/books?id=qhDFuWbLlgQC&printsec=frontcover#PPA322,M1

"In the times of Hubble (1920s and 1930s), these were the galaxies. In later times, ... the galaxy clusters took over. ... According to current beliefs, the elementary units of the universe should be groups of voids. These changes in the definition, adopted in order to save the assumption of homogenity ..."
Plebanski and Krasinski, http://books.google.com/books?id=uG9sDiUZJ94C&printsec=frontcover#PRA11-PA235,M1

 

[Dadface]

Frederick I agree that every physicist should be aware that a theory is not necessarily an absolute truth but in my experience this is a message that is not ,in general, getting through to the layperson.

 

[BoomBoom]

We obviously can't test the predictions about the past directly (since we can't go back in time), but we can certainly test the accuracy of the predictions about the present.

As far as the field of cosmology is concerned, this statement should really be switched around, shouldn't it?

Cosmology observations only deal with the past and there is no way whatsoever to observe the present. So the predictions (or assumptions rather) are really about what the universe is like in the present since there is no way to know for sure. The closest things we can observe (outside our local galaxy) are millions of years in the past.

 

[russ_watters]

Frederick I agree that every physicist should be aware that a theory is not necessarily an absolute truth but in my experience this is a message that is not ,in general, getting through to the layperson.

Then the laypeople need to pay better attention in middle school science class. If "the ordinary person on the street" wants to understand science, the basics of the scientific method are pretty straightforward - it's their choice to learn it or not. It isn't the professional scientist's responsibility to expend effort to teach people who have no interest in learning. That's not what they are getting paid for.

 

[Dadface]

There are plenty of people,in fact probably the majoritity, who simply do not have the time or the inclination to study the subject at the necessary level of sophistication and amongst that majority there are those who like to keep in touch with what is going on by reading popular ,non specialist magazines,or watching popular T.V. programmes.Are you telling me Russ Watters that those people should be told that they should have studied more whilst at school?

 

[russ_watters]

There are plenty of people,in fact probably the majoritity, who simply do not have the time or the inclination to study the subject at the necessary level of sophistication and amongst that majority there are those who like to keep in touch with what is going on by reading popular ,non specialist magazines,or watching popular T.V. programmes.Are you telling me Russ Watters that those people should be told that they should have studied more whilst at school?

Yep. But don't fret - if a 7th grader can learn it, so can an adult. It isn't hard. But they have to choose to learn it. No amount of effort from scientists can force someone to make that choice. If this was 7th grade, maybe we could force people to learn, but not for adults. For adults, they have to make the choice themselves.

 

[Dadface]

So you would tell an adult that he should have studied more whilst at school and if he doesn't get it your response would be that even a 7th grader can learn it.Nice one.

 

[russ_watters]

So you would tell an adult that he should have studied more whilst at school and if he doesn't get it your response would be that even a 7th grader can learn it.Nice one.

Someone who half-reads newspaper articles about science is not coming in here making a serious attempt to learn. But yeah, when we occasionally get people here who make quarter-hearted attempts, I slap them. That's what they need. I'm not going to sugar-coat and spoon-feed it to someone who isn't going to put in the necessary effort, especially since the necessary effort is so very small. My time is more valuable than that and they get more benefit from the slap anyway.

A quick anecdote: My dad is 65 and has two engineering degrees and a business degree. But he decided he wasn't getting enough out of our conversations about astronomy because his knowledge of the subject was a little thin. So for Christmas, he asked me for an astronomy textbook and now he's reading it cover to cover. That is effort. That is to be respected.

 

[atyy]

The big bang theory and every other theory we have are just that ,theories only and not necessarily truths and shouldn't this message,also, be passed more effectively into the public domain?

Are you thinking about eg. the difference in tenor between Carroll's and Schutz's comments?

http://blogs.discovermagazine.com/cosmicvariance/2006/08/21/dark-matter-exists/

"However, general relativity is simply a theory of physics, and it must always be tested against observation. ... The book is certainly not closed on new theories. If the dark matter particle is detected, much of the motivation to look at ideas like these will disappear. But if dark matter searches show that the required particles are not there, then scientist will take these theories much more seriously." Schutz, http://books.google.com.sg/books?id=...over#PPA404,M1

 

[cristo]

I disagree somewhat with Russ's opinion here, and I don't think that anyone slightly interested in science should be told to go and learn about it from textbooks. I believe that professional scientists should be, to some extent, responsible for disseminating their research to the average layman; or at least to those interested.

I don't, however, see how the average layman would think that we knew the answers to everything as mentioned in the OP, since if we did there would be not point in continuing research, would there?

A quick anecdote: My dad is 65 and has two engineering degrees and a business degree. But he decided he wasn't getting enough out of our conversations about astronomy because his knowledge of the subject was a little thin. So for Christmas, he asked me for an astronomy textbook and now he's reading it cover to cover. That is effort. That is to be respected.

That certainly is effort, but most people who are slightly interested in science are either unable to learn, or don't have the time. For example, I know a lot of non-scientists who are interested in cosmology and other theoretical physics, but don't have a hope in hell of being able to study it. I think it should not be forgotten that the average mathematics skills of a layperson amount to arithmetic, and most people have little to no knowledge of physics. This doesn't mean that they shouldn't be able to read about science, since most things lend themselves nicely to qualitative descriptions. They will never be able to perform calculations, of course, but they will get a general feel for what's going on, and the "wow" factor. I come across a lot of people who find out what I do and then go on to talk about a programme they saw on tv, or an article they read in the newspaper. They are never going to study a subject, but know enough to ask qualitative questions, some of which are pretty interesting. I don't think we should put such people off, in fact the opposite: we should encourage good popular science that reaches out to the average person on the street.

 

[russ_watters]

I disagree somewhat with Russ's opinion here, and I don't think that anyone slightly interested in science should be told to go and learn about it from textbooks. I believe that professional scientists should be, to some extent, responsible for disseminating their research to the average layman; or at least to those interested.

I didn't mean to imply that we should be telling everyone to read from textbooks - otherwise there would be no point to this forum! Most people here have a genuine desire to learn, which is why they come here. And most people who don't have a desire to learn half-read news articles and don't come here anyway. But we do get a few people here who make such a small effort as to be unworthy of our time.

Yes, threads like this really irritate me.

 

[Dadface]

It should probably not be within the remit of a forum like this to point out the limitations of theories unless specifically asked but it is something that science popularisers should consider more.It would be nice to hear occasional comments of the type referred to by atvy in his post above.I have known many people for whom big bang clashes with their personal beliefs but when I have stressed that it is a theory only they have gone away happy.

 

[cristo]

I have known many people for whom big bang clashes with their personal beliefs but when I have stressed that it is a theory only they have gone away happy.

What do you mean by "only a theory"? This just sounds like you're brushing it off. The standard cosmological model agrees with observations to an outstanding degree, and isn't "just a theory" in the same way that, say, string theory is a theory. I don't see why it matters what people's "personal beliefs" are. The laws of nature aren't going to abide by what someone does or doesn't believe in!

 

[matt.o]

I don't understand why they'd go away happy. A theory in science is placed on a much higher pedestal than mere personal belief. I guess ignorance is bliss, right?

 

[Dadface]

Cristo I am not "brushing off" the theory and of course there is excellent agreement between theory and observations otherwise it wouldn't be a widely accepted theory at all.Remember that theories are informed by observations and that they must conform to observations and remember,also, that observations are severely limited, so what do we really understand?Are you telling nature what she should or should not abide by?
matt.o.who placed science on a "much higher pedestal " than "mere personal belief".Could it be that some scientists have arbitarily elevated themselves as being sole owners of the truth?With the people I referred to previously I discussed the physics with them and made it a point to never get involved with what they believed in.I did ,however,respect that they had beliefs and I think they went away with some respect for the theory.

 

[cristo]

I did ,however,respect that they had beliefs and I think they went away with some respect for the theory.

This sort of comment implies that you are "brushing off" the standard cosmological model as "just a theory." Science, by definition, has to make predictions and agree with observations, whereas personal beliefs do not: you can make up whatever you like to believe in! Thus, for you to put personal beliefs and science in the same bracket is absurd.

Since this thread is more about science than actual science, I'm moving it to Philosophy.

 

[Gokul43201]

I have known many people for whom big bang clashes with their personal beliefs but when I have stressed that it is a theory only they have gone away happy.

I would say you've done the science a great disservice by taking on the standard creationist slogan of "it's only a theory".

I hope you will learn enough from this forum and any suggested references to understand what these terms mean and respect that a theory ought to be indifferent to beliefs and that it is something completely unlike what it has been bastardized into by proponents of creationism (and other such ideas).

 

[Dadface]

I fully understand what the terms mean and that it should be indifferent to beliefs and I would like to know where I have implied otherwise.I never discuss creationism or any other type of religion and as for other things that bastardise the theory I do not even know what these are.I do however discuss many things in physics including the big bang theory.The beliefs that I have been referring to are not my beliefs, they are the beliefs of some of the people I have discussed the physics with,physics and not a discussion of personal beliefs, and If I am to be a good and open minded physicist I would point out that theories have their limitations.Surely this is not wrong or detrimental to the subject.
The message put out by many science popularisers and many educators is that physics is nearly a fete accompli.This may not be accepted by many physicicists but it is accepted by many members of the general public and this is something that can be detrimental to the subject.

 

[Gokul43201]

I fully understand what the terms mean and that it should be indifferent to beliefs and I would like to know where I have implied otherwise.

You implied otherwise (or at least that's how I read it) when you described telling people that "it is a theory only" (final sentence of post#17).

The science behind whether or not computers should be possible is also a "theory only".

 

[Dadface]

Fine,a misunderstanding.What about my main point which can be expressed differently by stating that physics theories are continually being evaluated ,tested and in some cases modified or even replaced by a more powerful theory.That theories are not necessarily the truth and that physics continues to evolve and grow and that it is by no means a fete accompli.Should messages like this be passed more readily into the public domain?

 

[Gokul43201]

Fine,a misunderstanding.What about my main point which can be expressed differently by stating that physics theories are continually being evaluated ,tested and in some cases modified or even replaced by a more powerful theory.That theories are not necessarily the truth and that physics continues to evolve and grow and that it is by no means a fete accompli.Should messages like this be passed more readily into the public domain?

I wouldn't recommend messages as you have worded them. They make use of false dichotomies (such as theories being or not being the "truth") in attempting to explain how science works. I would much rather people learn (if they didn't already, in middle/high school) how science works from the ground up rather than the top down (especially if that top is misplaced).

You think the main problem here is that many people have certain misunderstandings about science, theories and so on, while I think most of those people do not have any understanding of these things at all.

 

[Dadface]

I agree that the wording has to be chosen very carefully.Thanks everybody for your feedback.

 

[russ_watters]

Fine,a misunderstanding.

I don't think it is a misunderstanding. You said people 'went away happy' after you described it as 'only a theory', which implies to me that the message you gave and they got was 'don't worry, it might not be true and your beliefs might be.' That's exactly the type of bastardization of science that I was complaining about in my posts!

What about my main point which can be expressed differently by stating that physics theories are continually being evaluated ,tested and in some cases modified or even replaced by a more powerful theory.That theories are not necessarily the truth and that physics continues to evolve and grow and that it is by no means a fete accompli.Should messages like this be passed more readily into the public domain?

The way you say it implies that the theory is much weaker than it really is. Whether you are doing that on purpose because of an internal conflict between belief and scientific knowledge (your post #20 implies it) or just plain due to ignorance of how science works is tough to know, but either way, what you said is a bastardization of science and you've done those people no favors -- unless ignorance is bliss and they prefer it. But I'd prefer if they were given the choice to learn or not learn science rather than having ignorance thrust on them by you.

 

[Dadface]

I did those people every favour because they went away with a good basic understanding of the theory and the evidence to support it.As for their personal beliefs then that is purely a matter for them and I would not be pompous enough to even try to begin to persuade them that they are wrong.I present the scientific evidence and what they choose to believe is up to them and not to people like you and me.As I said I never enter into discussions of a religious nature and as far as I understand it there is little conflict anyway between some religions and big bang,I may be wrong.
Where on Earth did I imply that the theory is much weaker than it really is?What does "much weaker"mean?Are you saying that the theory is weak but I have extended this to say it is much weaker.I have done no such thing.
I do not suffer from any internal conflict and I am not ignorant of how science works. I have done those people favours,they come to me for physics and physics is what they get,not a bastardisation of physics.They come to learn and learn they do the majority very well as evidenced by their results.Should I take it as an insult that you claim without any justification at all that I thrust ignorance on those people?My students certainly would.It seems you are reluctant to discuss the main points of this thread but prefer instead to go on a personal attack.

 

[Fredrik]

Where on Earth did I imply that the theory is much weaker than it really is?What does "much weaker"mean?

For example here:

What about my main point which can be expressed differently by stating that physics theories are continually being evaluated ,tested and in some cases modified or even replaced by a more powerful theory.That theories are not necessarily the truth and that physics continues to evolve and grow and that it is by no means a fete accompli.Should messages like this be passed more readily into the public domain?

When you emphasize that "theories are not necessarily the truth", you're sending the wrong message. You're suggesting that some of the very fundamental claims made by the theory can be completely wrong. In this particular case, you're suggesting (perhaps unintentionally) that maybe the universe was never in a hot dense state, and that suggests that maybe it isn't even expanding.

Theories are never "the truth". The statements that we accept as facts are statements about how well a theory agrees with experiment. That's the sort of thing that should be passed into the public domain.

you claim without any justification at all that I thrust ignorance on those people

You gave us plenty of justification when you said "when I have stressed that it is a theory only they have gone away happy". If that's what really happened, then you did throw ignorance at them.

 

[Dadface]

Thanks for your comments Fredrik.I have never suggested that the fundamental claims are wrong and I would never do such a thing unless I could justify it, which I can't.Any implied suggestion otherwise was unintentional and it seems that perhaps I needed to be more careful with my wording.
I agree wholeheartedly with your second paragraph and this is precisely the thing I have been trying to get across.
I do not agree that I throw ignorance at my students and I teach the facts as I knew them.What is one to do,however,when you get the occasional student trying to bring religion into the argument.In my case I don't even go there and I will never argue against someones religion. I will go back to the physics I will stress that big bang is a theory and you can make of it what you will.I can't remember a single case when someone has objected to this and people do go away happy the majority finding the whole topic fascinating.I don't know what other strategies I could use without causing offence.
Thank you again.I found your comments to be constructive.

 

[Astronuc]

who placed science on a "much higher pedestal " than "mere personal belief".

Well some people do. Back in the 40's, 50's, even 60's, the media portrayed scientists as heroes. There was a lot of popularization of science. Look at the popularity of Einstein and others.

However, science or rather the scientific method is supposed to be a rigorous process or application of logic, separate from prejudices, biases, and emotions. But humans, even those who practice science, are susceptible to prejudices, biases and emotions, and in some cases, dishonesty.

Belief is not necessarily rigorous, and in the extreme, is diametrically opposed to the scientific method, for instance when the belief continues/persists in the face of incontrovertibly contradictory evidence.

If people go away happy with the notion that 'a theory is just a theory', or 'only a theory', and their own misinterpretations are just as valid, if not moreso, then this is a disservice or diminution of science.

I think there are always niggling doubts, which are more about the completeness or incompleteness of a theory, rather than validity. On the other hand, we know we don't know everything, so one continues to test a theory and look for situations where the theory doesn't necessarily hold.

We're still looking for a GUT or TOE.

 

[Huckleberry]

What's kind of funny is that Dadfaces approach to teaching the layperson might be more effective, as long as the information itself is correct.

If someone holds a belief that contradicts a solid theory then there will probably be hesitation to accept the conclusions of that theory. It create's internal conflict that is irrelevant to understanding the concept. Saying "it's only a theory" downplays the effect the conclusion has on their belief. They can either dismiss or accept the results of the experiments and as Russ said, either choose to learn or not. This way they can come to terms with their beliefs at their own rate, rather than forcing the discussion into irrelevant areas.

Still not sure it's the right thing to do, but it's a lot easier to learn when you're happy and not frustrated.

Science looks for fact. When someone applies these facts to their beliefs they are looking for truth. Frustrating a person by challenging their beliefs will only make them defend those beliefs more fiercely, making the facts much more difficult to teach. The facts are forgotten and the truth is lost in the mix. A person who's identity isn't threatened will be more accepting of evidence. I know it can be difficult to dismiss terms like "It's only a theory", but for one sincere in the attempt to teach a layperson it's better not to take offense to it.