[littlebrowndragon (OP)]

I am not a scientist.  (I did maths and statistics at university).  To try to get to grips with secondary school level physics again recently, I borrowed a Teach Yourself Physics book from the library.  It was written by a physicist, an experienced physics teacher.   I must say that when I read the author’s  introduction I was somewhat taken aback.  The reason for my surprise was that the author stated that science cannot prove a theory, it can only disprove a theory.

This got me thinking, for example, of global warming.   The implication of the author’s statement is that global warming has not been proven.  Further, it cannot be proven.  Moreover, it has been accepted as a fact merely because of a consensus of opinion among scientists.  It seems to me to be no different from saying that 6 million people can’t be wrong about global warming. ( In truth, of course, 6 million people can be wrong about global warming or, indeed, anything else. )

Given that governments are making all sorts of treaties to combat global warming, treaties that impose a great burden on ordinary people , treaties that require considerable self-sacrifice on the part of you and me, I had thought that this was on the basis of proof, not mere opinion.

Is it correct that science can only disprove theories?  Or, not being a scientist, have I misunderstood the situation?  Could forum scientists please shed some light on this for me?


Thanks,

A very confused littlebrowndragon 

[Halc]

The implication of the author’s statement is that global warming has not been proven.  Further, it cannot be proven.  Moreover, it has been accepted as a fact merely because of a consensus of opinion among scientists.

Indeed it (or any other scientific finding) cannot be proven, but that doesn't mean it has been accepted merely because of people's opinions.  Things that have been accepted are due to a very high probability of being the case.
So for instance, one cannot prove that momentum is conserved, but no example of violation of this rule has ever been demonstrated, so the law is considered fact.  Likewise, global warming has an overwhelming probability of being the case, hence it is considered fact by those using science, instead of biases, to draw their conclusions.

[chiralSPO]

The various theories that climate change is NOT human-driven has been fairly thoroughly disproven.

ie "the extra CO₂ is from volcanoes" doesn't hold up to scrutiny because the ratio of isotopes of "excess" C matches the isotope ratio found of fossil fuels, and the ratio of O isotopes matches what is currently in our air, not what is in carbonate rock. (https://www.wired.com/2015/04/volcanic-versus-anthropogenic-carbon-dioxide-addendum/)
~~~
Since the OP mentions a background in maths and statistics, I would also draw attention to the ideas of Risk Analysis, and Type I error (false positive) vs Type II error (false negative). Because we can never be absolutely sure of anything (barring logical tautology), there is some associated uncertainty with any determination.

Let us imagine that I have a bowl of oysters in front of me. Unfortunately some of them have gone off, and could sicken me if I ate them. By giving each one a quick sniff, I have a 90% chance of identifying (correctly) that a bad one is bad (leaving a 10% Type II error), and a 60% chance of of identifying a good one as good (40% Type I error).

I can't REALLY know, based on any given smell test whether a negative result is a true negative or a false negative. (and likewise with positive). If I don't know what percentage of oysters is bad, then we have little to go on. Let's assume half of them have gone bad. (NB: The analysis changes slightly if we decide on a Baysian or Frequentist approach https://www.probabilisticworld.com/frequentist-bayesian-approaches-inferential-statistics/)

In that case, given that an oyster smells bad, there are two possibilities:
it is bad (50%) and I identified it correctly (90%) (0.9×0.5 = 0.45)
or
it is good (50%) and I identified it incorrectly (40%) (0.4×0.5 = 0.2)
so it looks like if it smells bad it is more than twice as likely to be bad than to be good.

or, if the oyster smells good:
it is bad, and I identified it incorrectly (0.5×0.1 = 0.05)
or
it is good and I identified it correctly (0.5×0.6 = 0.3)
so given that it smells good, the chances of it being good are 6 times better than it being bad.

But here's the thing: I don't like those odds. I have gotten food poisoning from seafood before--it's very unpleasant. And yeah, oysters taste ok... but if I multiply out the various probabilities by how MUCH I stand to gain or lose in each scenario, unless I am literally starving to death, I would not eat a "good smelling" oyster if it had a 1/7 chance of making me ill (and I DEFINITELY wouldn't eat several "good" ones with those odds--I would certainly poison myself).

risk = ∑((probability of something happening)×(how bad it would be if it did happen))

So, back to climate change. Given that our indicators are all pointing to CLIMATE CHANGE IS REAL and CLIMATE CHANGE IS BAD, we have to ask ourselves three questions?
• How likely is it climate change is not happening (type I error)? P
• How bad is it if we act as if climate change is happening and it's not? (type I hazard) A
• How bad is it if we act as if climate change is not happening and it is? (type II hazard) B

risk = P×A + (1–P)×B

I posit (and countless studies support me on this) that P is really really small (like 10^–6), B is really, really big (like $10¹⁷), and A is still big, but not as big (like $10¹⁵)


Ultimately:

hoax.png (451.86 kB . 780x516 - viewed 2572 times)

[alancalverd]

Science is the application of the algorithm: observe, hypothesise, test (by further observation), repeat until satisfied.

Scientific knowledge is the residue of explanatory and predictive hypotheses that have not been disproved by test.

Specifically, climate change is an observation. It is inevitable because the atmosphere and biosphere is inherently unstable. We know that it has been both hotter and colder within recorded history,  and by inference from ice samples, we can see periods of rapid heating followed by slow cooling going back over  400,000 years. We are now in a period of rapid heating.

We also observe a correlation between mean surface temperature and the concentration of carbon dioxide in the atmosphere. However the ice core record shows a lag of 500 - 800 years between temperature and CO2 level, which suggests that CO2 is, or at least was, the thermometer (effect) , not the thermostat (cause).

We also know that atmospheric water is the primary determinant of surface temperature and the quantity of water in the atmosphere is variable (from 0 to 10% as gas) inherently unstable, and cyclic. Unfortunately we have no historic record of cloud cover or atmospheric water content generally, and even the short term behavior is very complex as water exists in all three states (solid, liquid and gas) at all levels, simultaneously, with huge quantities of energy involved in the isothermal processes of melting and evaporation.

There is a current consensus that anthropogenic carbon dioxide is driving the present warming phase. This hypothesis is attractive for many reasons but (a) it runs contrary to the historic record and (b) it has not been tested. The only applicable test is, obviously, to reduce or eliminate anthropogenic CO2 and see what happens, but the whole of animal life depends on the oxidation of carbon compounds, and the quality of human life, since the invention of fire, is directly related to the controlled production of "artificial" carbon dioxide in industry. Very few people can survive without burning fossil fuel or wood - only vegetarians in tropical forests, which are being destroyed anyway, and a few coastal communities whose shallow fishing grounds have not been denuded by industrial trawling.

The history of science, indeed of mankind, is littered with dead ends and disasters caused by spurious correlations, convenient consensus, and bizarre beliefs about the dominion of homo sapiens (or particular subspecies) and various forms of karma and nemesis. If we avoid all these, we can conduct a rational experiment to test the hypothesis of anthropogenic climate change by simply reducing the number of humans on the planet. Natural death will do the work for us, reducing the population to about half in 35 years with no other input, but there will be nobody around in 100 years' time to benefit from the result. If we just limit  the input to one child per female, our successors will inherit a controllably declining population with increased per capita natural resources and a steadily declining need for artificial CO2.

This would be a Good Thing  anyway. If climate change is inevitable and the population continues to grow, there will be mass migrations in the foreseeable future from unsustainable arid or coastal communities, leading to major wars and/or mass starvation. Fewer people = less pressure. If reducing anthropogenic CO2 emission does reverse warming, we will have taken control of the environment with no detriment, and eventually a significant improvement, to the quality of life of our descendants, by doing nothing!   

[jeffreyH]

It is exactly because we have too many people on the planet that we have exacerbated climate change. We have hurried the process up. A village of a thousand needs very little fuel. A planet of billions requires a huge amount of fuel. All the processes are magnified. Whatever it is we are doing to the water cycle we are doing it on an unprecedented scale.

[jeffreyH]

BTW If you don't believe this view go and check out Puerto Rico and the Bahamas. That is our effect on the water cycle. Don't believe me? Fine.

EDIT: Check out how much rain Texas has just had.

[littlebrowndragon (OP)]

OK, thanks a lot for those very comprehensive responses to my question.  I'm going to have to mull them over before replying to them!  Meantime, thanks again.

[littlebrowndragon (OP)]

Things that have been accepted are due to a very high probability of being the case.So for instance, one cannot prove that momentum is conserved, but no example of violation of this rule has ever been demonstrated, so the law is considered fact.

Thank you for your response.  It raises questions in my head.  So, here goes……. 

Ok, the violation of this rule – the conservation of momentum – has never been demonstrated.  Suppose, however, I’m out for a walk one day and I somehow observe the rule being violated.  Only, being a non-scientist and especially a non-physicist, I do not even know I’ve seen the rule being violated.  What then?  The rule has been violated, even if I cannot demonstrate that it has been violated, even if I do not even know that I have seen it being violated, and yet science, not knowing what I have seen, still insists that the conservation of momentum is a law (or rule).  How does science deal with this sort of scenario, would you say?

A more fundamental issue, I think, is that it appears that science sees the world, the universe, as operating by rules.  I assume that this is also down to statistics i.e. there is a very high probability that the natural world operates by rules (cause and effect?) and so this is now considered fact.

In fact, how does science define what a “fact” actually is, do you know? 


I’m afraid I have a lot to learn about science.  Thank you for your patience!

[Bored chemist]

There are e few rules that we can prove (given certain condition). Momentum conservation is one of them.
Here's the proof- I have to admit I don't understand it.
https://en.wikipedia.org/wiki/Noether%27s_theorem

[Halc]

Ok, the violation of this rule – the conservation of momentum – has never been demonstrated.  Suppose, however, I’m out for a walk one day and I somehow observe the rule being violated.  Only, being a non-scientist and especially a non-physicist, I do not even know I’ve seen the rule being violated.  What then?

I think then the violation will go unnoticed. But it also means the foundation of physics is in fact mistaken, even if nobody yet knows it.
Once it becomes noticed, everything build on that invalid assumption will have to be rebuilt.  That's a lot of books to rewrite.

The rule has been violated, even if I cannot demonstrate that it has been violated, even if I do not even know that I have seen it being violated, and yet science, not knowing what I have seen, still insists that the conservation of momentum is a law (or rule).  How does science deal with this sort of scenario, would you say?

Science would not deal with it because you, not knowing that you're witnessing something amazing, have not reported it.

If you know it is wrong, then you're a physicist and they would act to reproduce the phenomenon, in order to posit the beginnings of new rules.
There are claims all the time of such violations (of one rule or another), but none have been verified.  The conservation laws are the most difficult to assault.  Other findings are less cast in stone, like "use of product X makes you more attractive to others".

A more fundamental issue, I think, is that it appears that science sees the world, the universe, as operating by rules.  I assume that this is also down to statistics i.e. there is a very high probability that the natural world operates by rules (cause and effect?) and so this is now considered fact.

In fact, how does science define what a “fact” actually is, do you know?

I suppose it is something that has a sufficient consensus among those with sufficient knowledge and detachment in the subject matter


I’m afraid I have a lot to learn about science.  Thank you for your patience!
[/quote]

[Janus]

Things that have been accepted are due to a very high probability of being the case.So for instance, one cannot prove that momentum is conserved, but no example of violation of this rule has ever been demonstrated, so the law is considered fact.

Thank you for your response.  It raises questions in my head.  So, here goes……. 

Ok, the violation of this rule – the conservation of momentum – has never been demonstrated.  Suppose, however, I’m out for a walk one day and I somehow observe the rule being violated.  Only, being a non-scientist and especially a non-physicist, I do not even know I’ve seen the rule being violated.  What then?  The rule has been violated, even if I cannot demonstrate that it has been violated, even if I do not even know that I have seen it being violated, and yet science, not knowing what I have seen, still insists that the conservation of momentum is a law (or rule).  How does science deal with this sort of scenario, would you say?

In some cases, such as the above mentioned conservation of momentum, it isn't just a case of a violation never being observed, but a case that if it weren't conserved, the world we live in wold look a lot different than it does.  You would see examples of it not being conserved everywhere.  (this is something where many inventors of "perpetual motion" devices run afoul.  They devise these complicated systems designed to "side step" the conservation of energy, without realizing that if energy conservation could be violated, it could be done so much more simply and directly.  All their complications do is make it easy to lose track of the energy transfers.) 
 
Going deeper, there is an actual mathematical proof*( Noether's theorem) that show that certain physical systems have to have conserved quantities.

* in mathematics, it is possible to produce proofs.

[littlebrowndragon (OP)]

Because we can never be absolutely sure of anything

How do you know this?  Since this is a science site, are you speaking for science?  Are you saying that science can never be absolutely sure of anything?

[Kryptid]

How do you know this?  Since this is a science site, are you speaking for science?  Are you saying that science can never be absolutely sure of anything?

It's just technically true. Any and all observations have the capacity to be mistaken.

[alancalverd]

The line between science and engineering is drawn by the concept of "good enough". We had pretty good scientific models of  how electric current and magnetic fields relate, sufficient for Edison and the like to develop the public electrical grid in an entirely useable form, but the detail of electron and hole conduction in metals wasn't worked out for a long time afterwards. There is an old saying that "thermodynamics owes more to the development of the steam engine than the steam engine owes to the study of thermodynamics". Science is often about solving problems arising from the failure of apparently obvious engineering projects. So data and laws that may be good enough for today's application may turn out to need  a bit of tweaking tomorrow. Which is yet another reason why science is all about humility and evolving hypotheses, in contrast to politics, philosophy and religion, which are vanities based on absolute certainty.   

[evan_au]

This got me thinking, for example, of global warming.   The implication of the author’s statement is that global warming has not been proven.  Further, it cannot be proven.  Moreover, it has been accepted as a fact merely because of a consensus of opinion among scientists.  It seems to me to be no different from saying that 6 million people can’t be wrong about global warming

I think what you are saying is that global warming has been proven wrong because one person (not a climate scientist) said it was "fake news".

He can't prove his assertion is true, either.

So you are left with probabilistic calculations like those demonstrated by chiralSPO.

There are groups who clearly stand to lose if the true costs of CO₂ emissions are included in economic calculations - the coal and oil industries are clear examples. That is why they are funding big advertising campaigns and political candidates to fight against a realistic cost assessment. That is why the US EPA, NASA and NOAA are being restricted in what they can say (or legislate, in the case of EPA).

Another case involving the EPA occurred with lead in petrol, in the 1980s (under Reagan).
- Similar to today, the EPA was told to reduce costs for industry - and one industry efficiency they were told to implement was to relax the limits on lead in petrol.
- They had to look into it before blindly implementing it
- As I recall, they worked out the cost savings as something like $100 million. That would have been enough savings to implement it.
- However, some statistics on the association between lead in the blood and IQ were used to show that this would dumb down the population (and the use of IQ statistics was somewhat controversial)
- Some statistics on income and IQ showed that this would reduce individual earning capacity
- This would cause a health impact of something like a $billion
- This was something that the EPA simply could not ignore
- So the EPA ignored the government directive and made the limits on lead 10x tougher

Lead in petrol affects children in utero now. This impacts the next election.
People can argue that the biggest impacts of global warming will be felt in 50-100 years, which is after the next election, and so politicians feel they can safely ignore it.
Listen, or read the transcript: https://www.wnycstudios.org/podcasts/radiolab/articles/g-problem-space

[alancalverd]

The elephant in the CO2 room is transport. A few very rich people can afford electric cars which are 30% powered by unreliable sources of electricity, which makes reliable electricity more expensive. I  suspect the people who run electric cars would be the first to complain if the lights went out in the operating theater. However the lesson from history is that during miners' strikes and 3-day weeks, the UK government insisted that football stadiums, entertaining tens of thousands, should not use floodlights, whilst the Royal Opera House was exempt.

The standard of living of almost everyone else depends on burning carbon fuel, if only to take your hand-carved ethnic wooden spoons  to market. 

The current joke is that the prospective developers of the "low carbon, Good Thing" HS2 rail link between London and Birmingham have bought swathes of good commuter land at your expense and transferred it to the ownership of the private companies that have so far spent over £20,000,000,000 on consultancy fees to one another and not laid an inch of track. Now there is an excellent prospect that the project will be cancelled, and the land can be used to build houses, all unremarkably close to existing roads and railways and therefore highly desirable residences. Whoopee! Massive bonuses for the already-rich!  All we need to do is cut down a few forests and fire up some furnaces to make the concrete.

[Bored chemist]

The elephant in the CO2 room is transport.

Yes, it is.
So, we need to think of low CO2 options.
At the moment electricity from renewables is a bit hit + miss.
But, and here's the important bit, it's getting better.
While the CO2 levels in the air are getting worse.

So, we need to concentrate on improving the stuff that already works.

Pointing  out that rich people are selfish bastards is also a reasonable act.
But it's not strongly related to global warming, except that the ones who currently own the fossil fuel  infrastructure are protecting their investments by badmouthing  low carbon alternatives.


Why are yo helping them?

[littlebrowndragon (OP)]

The history of science, indeed of mankind, is littered with dead ends and disasters caused by spurious correlations, convenient consensus, and bizarre beliefs

When the first atomic bomb was tested, I believe that scientists back then were concerned that when the bomb was activated i.e. exploded, it could possibly create a chain reaction causing the destruction of this planet.  Yet they went ahead anyway.  Is this correct, do you know?

“Dead ends and disasters” brings to mind a well known character from Scottish literature called Para Handy.  He was captain of a puffer, a small coastal cargo vessel.  (These boats are now extinct.)  The best way to describe the fictional Para Handy is to relate a story from my childhood involving the captain of a small fishing boat.  He was nicknamed Para Handy and was one of my father’s cronies (my father was very keen on boats). 

My father’s friend, Para Handy, was out with my father and some friends as well as my father’s family i.e. my mother and myself and my sister, for a pleasant summer afternoon’s cruise.  Drink had been consumed.  Para Handy was very drunk.  On the way back into the loch, Para Handy locked himself into the wheelhouse and, applying full throttle, steered his boat straight at the pier.  None of the other men on board could get into the wheelhouse to put a stop to Para Handy’s antics.  The pier was getting very close very fast.  The women present took their children under their arms to the back of the boat where they braced themselves for impact.  There was nothing the other men could do to gain entry to the wheelhouse.  A serious collision seemed inevitable.  At the very last minute, Para Handy unexpectedly unlocked the door and walked out of the wheelhouse, the boat still full steam ahead for collision.  One of the men then managed to grab the wheel and pull the boat round, missing the pier literally by inches.  Some time later, Para Handy actually wrecked that boat.  He was later made captain of a puffer which he wrecked.  Later still he was made captain of a steamer (a passenger vessel) which he also managed to wreck.

I am no spring chicken.  I have been around long enough and have had enough experience of the world to see how untrustworthy people are and that the world is going downhill.  I can see how badly people behave because they are corrupt i.e. they are power hungry, they are self-seeking, they are highly competitive, they empire build etc, etc.   I’ve seen it in every walk of life: in business, in education, in the church etc, etc.  Even in hospital during a lengthy stay there last winter, this corrupt behavior was evident.  Clearly there are plenty of Para Handys in all these walks of life.

As to science, it is captain of this world.  If this captain is a Para Handy (i.e. responsible for all those dead ends and disasters) then it doesn’t matter if science is any good because a bad captain like Para Handy is going to sink the boat and take all hands with him.   

[Bored chemist]

Science has no captain.
One bad scientist usually just ends up making a fool of himself- though others may get hurt in the process.

So, if there's a Para Handy involved, it will be a politician (like Trump or Boris) who ignores the advice of the scientists- and the other experts- and does something stupid anyway.

I have been around long enough and have had enough experience of the world to see how untrustworthy people are and that the world is going downhill.

It always has been going down hill- if you look at the papers.
But if you look at wealth of the people  or life expectancy or new discoveries in medicine, it's actually always getting better.

When the first atomic bomb was tested, I believe that scientists back then were concerned that when the bomb was activated i.e. exploded, it could possibly create a chain reaction causing the destruction of this planet.  Yet they went ahead anyway.  Is this correct, do you know?

Well... they did the calculations which showed that the end of the world wasn't going to happen.
But there is no way they could be absolutely sure of anything.
They didn't know if the bomb would even work; that's why they tested it.

[littlebrowndragon (OP)]

I think then the violation will go unnoticed. But it also means the foundation of physics is in fact mistaken, even if nobody yet knows it.Once it becomes noticed, everything build on that invalid assumption will have to be rebuilt.  That's a lot of books to rewrite.

More than just a lot of books to rewrite.  That is trivial in comparison to the consequences for people in general.  If science gets it wrong, then people’s lives are at stake.

Science would not deal with it because you, not knowing that you're witnessing something amazing, have not reported it.

My suspicion is that, being a layman, science would be unlikely to take my claim that I saw the rule violated at all seriously.  I suspect a lot of non-scientists would have to have observed the phenomenon before science would sit up and listen.

If you know it is wrong, then you're a physicist and they would act to reproduce the phenomenon, in order to posit the beginnings of new rules.

I do not know the truth of this, but I have heard that science is not above hiding inconvenient evidence if uncovered.  I have heard it said that palaeontologists have unearthed some strange “fossils” such as, I think, a modern human shoe and that the presence of this “fossil” shoe, if made public, would be a great embarrassment to these paleaontologists.  It would call into question much of their work.   I am not the only person to have picked up on this.  For example, I can think of at least one piece of fiction where the author has used this as the basis of their story.

A piece of non-fiction this time: Bill Bryson’s A Short History of Nearly Everything.  (This book is, in fact, a short history of science.  The title is misleading.)  In it there is a chapter on early palaeontology.  Bryson describes the antics of certain 18th or 19th century (can’t remember which century) palaeontologists, French, British and American.  I can only remember one name, de Buffon I think it was, a French scientist.  Anyway, Bryson describes their competition, a matter of national pride supposedly, to lay claim to finding the biggest, most spectacular fossil dinosaur.  What each group of palaeontologists did was to cobble together the biggest and most impressive bones into some skeleton of a supposed dinosaur.  The truth had nothing to do with it.  It didn’t matter if the skeleton was anatomically impossible, just shove in any bone anywhere and make the fossil as impressive looking a dead animal as possible.  The nation which produced the biggest fossil would, of course, be the winner.