How do I show a skeptic that atoms/molecules actually exist?

  • #76
Drakkith
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Actually the progress of science helps us build instruments that allow us to see new physical phenomena (reality) that were previous unavailable to us.
The point is that 'reality' may be wildly different than what we think, we just can't tell.
 
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  • #77
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The point is that 'reality' may be wildly different than what we think, we just can't tell.
I still think that is confusing the ideas of having a perfect, fundamental theory with the phenomena that we observe. If it is raining on my head, I believe this is an objective fact that everyone around me agrees with. We all agree that the phenomena is happening. What could possibly be wildly different about that observation?
 
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  • #78
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I would recommend your friend learn about the experiments of Dalton, Milikan, Rutherford, Thomson, and others. Each experiment discovered something about the atom. It was a black box. You could indirectly guess what was inside, but you could not see. These days, you could see the valence shells of atoms using an electron microscope.
In a metaphysical sense, we don't. In the context of science, their existence is supported by the known rules by which all of these particles decay. It's a bit like measuring the decay products and decay rate of an unknown sample. Given enough decay events and enough time relative to the decay rates, you can make a reasonable conclusion as to the different elements the sample is composed of.
The point is that 'reality' may be wildly different than what we think, we just can't tell.
Although I am mathematically oriented, in such cases I am usually not a skeptic at all and I am usually happy accepting the obvious that we see, going by the simple, practical old-fashioned rule/method/criterion:
"If it looks like a duck, walks like a duck, talks like a duck ... , well ... it's probably (most likely) a duck!"
And it doesn't matter what you call them, or what you think they are. It's what they are.
 
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  • #79
Drakkith
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If it is raining on my head, I believe this is an objective fact that everyone around me agrees with. We all agree that the phenomena is happening. What could possibly be wildly different about that observation?
It could be an artifact of another, unobservable process.
 
  • #80
A.T.
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I still think that is confusing the ideas of having a perfect, fundamental theory with the phenomena that we observe. If it is raining on my head, I believe this is an objective fact that everyone around me agrees with. We all agree that the phenomena is happening. What could possibly be wildly different about that observation?
You could wake up, and find it was just a dream. That would change your interpretation.
 
  • #81
Mark Harder
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You could show him the photographs.
Electron microscopy has "photographed' atoms and molecules in crystals. Mechanical microprobes can image atoms and molecules by feeling their way across solid surfaces. It is even possible to move individual atoms with laser light, and get them to spell "IBM" or some such. We know this because we have photographed the result, and I guess, stages in the process. He may object that such photographs are highly artificial, that the instrumentation and the electronic processing is making what we see. But really, so is seeing an object with our eyes - and brain. How does your friend know that you are real? Oh, that's right this is internet reality. Well, then ask him how he knows the friends he actually does see are real. What's the difference? This could get real philosophical real soon..
 
  • #82
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It could be an artifact of another, unobservable process.
You could wake up, and find it was just a dream. That would change your interpretation.
I think I understand what you are both saying. That we cannot prove our experience and the metaphysical reality of the phenomena with absolute certainty using the scientific method. But I think this is where probable versus possible comes into the picture (like the statement in your signature @Drakkith).

If we use the Bayesian approach to update our priors and assess the probability that our experience of phenomena is justified by X observations and experiments, we should find it quite improbable that we are just brains in vats. It would be probable to find anomalies in the phenomena and our experiences of them. Therefore, in my opinion, it is an infinitesimally small chance that the phenomena do not reflect reality. And I would say that it is far more rational to accept that conclusion based on the probabilities. The assumption of realism seems to have no evidence to the contrary in my view. And any invented theory that is more fundamental than quantum field theory would still seem to have to approximate to our everyday experience in the proper domain.
 
  • #83
bob012345
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Actually you cannot see electrons. You can see a shell since these particles are moving so rapidly that they appear to be a solid. We can visualize a proton or a neutron which are large enough to see. Now I haven't done this sort of work since the late 2000's but the papers I've seen since then are not very encouraging. More and more I distrust any and all studies and too many degrees seem to have been achieved with "book larnin" and no practical experience. Why the hell would you advertise for a PhD with no experience for a job that requires extensive experience in dozens of different standards and years of experience in three or four different programming languages?
I didn't suggest one can literally see electrons, just sense their effect. You can't literally see a shell filled with electrons either. The STM pictures are representations of the electrical probe signals. People hire PhD physicists because they have been trained to do science, not always because they already have certain skills or because of their thesis work directly. Sometimes that's relevant of course. When I hired on with a large semiconductor company my skills really only included a broad background in theory and little practical experience in semiconductor devices design or manufacturing processes yet I quickly learned both on the job. Most of the PhD level people were similarly hired and were working on things very different from what their thesis work was.
 
  • #84
A.T.
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Therefore, in my opinion, it is an infinitesimally small chance that the phenomena do not reflect reality.
How did you calculate that probability?
 
  • #85
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How did you calculate that probability?
I did not do any quantitative calculations. I am not sure if the calculation can be done. But, I still assert that if we are analyzing the hypothesis that physical phenomena and our observations do not give us true knowledge of reality, then each experiment and observation that verifies the same physical phenomena for X observers updates our knowledge and makes the hypothesis very unlikely. Just in a broad, hand-wavy fashion. :smile:
 
  • #86
A.T.
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I did not do any quantitative calculations. I am not sure if the calculation can be done. But, I still assert ...
AKA "the scientific method".
 
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  • #87
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I think a dose of Feynman is in order here:

The essence of science is doubt backed up by observation.

Why do we believe in atoms?. Around the time Einstein was learning physics their was a big debate about it. Einstein was chided for actually believing in atoms during his student days. But you see we have this phenomenon called Brownian motion. Einstein explained it using atoms and it was in agreement with experiment. Nobody could really explain it any other way so things gradually changed and eventually everyone believed in atoms. Does that mean atoms exist - no - the essence of science is doubt - its like 2+2=4 - that almost certainly is true - we even have proofs that make doubting it rather difficult - so difficult mathematicians would be inclined to say its as true as anything can be . But is it? No - we must doubt even that. Its just a working hypothesis we accept for now and admit future knowledge may make us seem like fools. That is the essence of science - that is what anyone interested in science must have as part of their very essence. That's what Feynman knew and why everyone needs to watch and re-watch Feynman.

This is the precise reason we do not live in a scientific age. Even in science some don't get it - outside science its all over the place - and IMHO is one of the main reasons, if not the main reason, for the mess we find ourselves in - but that is not what this forum is about. We are about science - even applying it to the domain that originated it is hard enough - going outside that - ?:)?:)?:)?:)?:)?:)?:)?:)?:)

An example is climate change. We hear all sorts of views - some so silly its sickening. But here are the facts. There is a difference between climate and weather. We are seeing changes in weather - the Eastern seaboard of Australia for example is getting hotter. Is this caused by global warming? Ask a genuine climatologist and they will say something rather complicated called attribution (at least I think that's what its called - it not an area I am right up on) needs to be done before anything can be said one way or the other. It has not been done yet, still people warble on and on with all sorts of differing viewpoints. We don't live in a scientific age - we live in an age where many don't even understand science or its methods yet invoke it all the time for their own ends.

The solution - Feynman says it - science is about doubt - not certainty - run a million miles from anyone that uses science to make claims not backed by strong evidence verified by others - and even then always carry around doubt.

Thanks
Bill
 
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  • #88
Khashishi
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I've met people like this. Strange how they can sometimes seem to be extremely intelligent and knowledgeable about many things and yet be completely screwed up in the head. I know someone who knows quite a bit of history but is convinced that everything in modern science, including all of quantum physics and relativity, is a lie perpetrated by the Jewish industries, and that Einstein stole all his ideas and that aether physics is correct. Also, that Birkeland currents were somehow responsible for various phenomena in cosmology.

It was hopeless to try to convince them otherwise.
 
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  • #89
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I would use some of the following facts to argue, largely chemistry based ... these are not fact checked. If there is an egregious error, please correct me.

1.
2 volumes of hydrogen gas, react with 1 volume of oxygen gas, to yield 2 volumes of water gas, at the same temperatures and pressures.

2.
2 grams of hydrogen reacts with 16 grams of oxygen to give 18 grams of water.

3.
Elements are fungible. You can take any 2 grams of (naturally occurring) hydrogen and it reacts like any other 2 grams of (naturally occurring) hydrogen.

4.
You can find hydrogen (we know it as deuterium) that reacts EXACTLY like any other elemental hydrogen, except 4 grams of hydrogen reacts with 16 grams of oxygen to give 20 grams of water. That hydrogen still reacts the same volumetrically: 2 volumes of hydrogen gas, react with 1 volume of oxygen gas, to yield 2 volumes of water gas, at the same temperatures and pressures.

5.
The elements can be arranged quite nicely in a Periodic table, where the columns have similar chemical properties.

6.
2 grams of hydrogen gas occupies twice volume as occupied by 16 grams of oxygen (at the same temperature and pressure).

7.
Elements are electrically neutral.

8.
Reacted elements are sometimes ionic and can be moved by electrical fields. Other reacted elements are not.

9.
If you electroplate out an element, you get a proportional amount of the element to the current.

10.
Gases diffuse. At different rates. Hydrogen diffuses 4 times faster than oxygen.

These are just bits of chemistry that are best explained by an atomic theory, based on the quantum atom. There are also lots of good bits of physics ... Brownian motion, particle accelerators and particle movement in electric fields that allow a charge-to-mass ratio to be determined. The Micholson oil-drop experiment that shows a discrete smallest unit of charge. The demonstration that the "hypthetical" atom is a dense positively charged heavy part, and then largely empty space surrounding that.

One theory, atomic theory, predicts and explains a LOT of chemistry and physics. It explains the mass ratios of chemical reactions. It explains the volume ratios of gases in chemical reactions. It explains the periodicity of elements. It explains the movement of ions in charged fields. It explains gaseous diffusion. It explains everyone of those facts, and more.

Sure. it is just a theory. But that sounds like a flimsy word. It is a well-supported theory. It has been agreed by everyone that "theory" is the correct word, and that even a radical change in theory could happen.

It just seems purposeless to regard atomic theory as anything but reliable. The chemistry of the elements is precise and reproducible. And in every way behaves as though small discrete (and completely fungible) atoms are reacting.

And it is also true that if tomorrow a theory that uses waves instead of particles comes along, and does a better job of describing things, I will re-learn that basis of chemistry.
 
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  • #90
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I am having a debate with a friend of mine over the Internet. It is about science. ...
...
So, likewise he says that although we use electricity, make atom bombs, create drugs and chemicals (i.e. technology), we actually don't know whether atoms or even molecules really exist. He says that we really don't know whether protons, neutrons or electrons really exist.
Why? (Asking for a friend ;) )
We all call it "a friend" now ... don't we? :smile::wink:
A [skeptic] friend just asked me too:
"Does my brain really exist?" (i.e. his brain)
Of course I knew how to answer with ease:
"I don't see it, ... so I guess not! ..."

(Perhaps that's the best [sarcastic] reply to "all our skeptics friends", or better yet, perhaps, to our "skeptic selves" ...)
 
  • #91
russ_watters
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A [skeptic] friend just asked me too:
"Does my brain really exist?" (i.e. his brain)
Of course I knew how to answer with ease:
"I don't see it, ... so I guess not! ..."

(Perhaps that's the best [sarcastic] reply to "all our skeptics friends", or better yet, perhaps, to our "skeptic selves" ...)
Follow-up: And I know mine exists, because talking to you is making it hurt!
 
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  • #92
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A [skeptic] friend just asked me too:
"Does my brain really exist?" (i.e. his brain)
Of course I knew how to answer with ease:
"I don't see it, ... so I guess not! ..."
I'm sure this thread will soon be locked, but for what it's worth...

I think Descartes argument about, "I think therefore I am." is still a rock solid argument to justify existence. Although Augustine of Hippo said the same thing back in the early 5th century AD.
 
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  • #93
hilbert2
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This thread is giving me a mental image of a situation where someone claims that Earth is actually a hollow shell that's 100 kilometers thick, and insists that we must drill a hole deep enough in the ground to show that he's wrong...
 
  • #94
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This thread is giving me a mental image of a situation where someone claims that Earth is actually a hollow shell that's 100 kilometers thick, and insists that we must drill a hole deep enough in the ground to show that he's wrong...
And the proper response: hand him a shovel and tell him to get to work.
 
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  • #95
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But of course there is the scientific aspect of this thread, e.g. scientifically supporting and proving the existence of atoms, molecules etc. (with the scientific method). To me, today, these are secure scientific realities, and I think most rational scientists would have to agree ...
 
  • #96
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I am late in this, and didn't go through all the replies, but your [the OP] friend's argument about Newton and Einstein is exactly why science is working. Because it changes to new discoveries if the existing models and theories fail to explain them. It doesn't tell the absolute truth, but from the available data it builds a model to explain existing phenomena, and make predictions about the past or the future. No one says these models are the absolute unchanging truth or the reality. After all, what is reality? Is what we see the reality? The visible light we see is a tiny fraction of the EM spectrum. Other animals see and hear things we don't see and hear. I remember Stephen Hawking addressed this in the beginning of his book A Brief History of Time.
 
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  • #97
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I'm sure this thread will soon be locked, but for what it's worth...
Yes, thread is closed for a bit for Moderation...
 
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  • #98
berkeman
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Thread will remain closed, unfortunately. There have been a number of very good replies in the thread, but unfortunately a discussion like this can attract incorrect things like this:
There are a number of physicists that are entertaining the idea that we are in a simulation. That is, there is a higher reality in which our simulation is running. This is perhaps due to VR which is getting good enough to make such an idea conceivable and that we may soon be able to build our own worlds with simulated intelligent entities that could be totally unaware that they are being simulated. So reality could be relative to what universe you live in and, in the end, doesn't make any difference.
Unfortunately, there are too many posts like this mixed into the quality discussion, and it makes it hard to clean up such a long thread to keep it open.

So, unfortunately this useful thread will need to remain closed. Thanks for all of the good-quality responses. :smile:
 
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