When do neutrinos, black holes, quarks, dark matter, and dark energy become real?

[Nereid]

The thread title is an abbreviation of a question I wrote in this Astronomy section thread: At what point do electrons, photons, neutrinos, black holes, quarks, dark matter, and dark energy stop being useful concepts (to help theories get sharper and better) and become real?

Disinfo Agent said it was a good question, and asked me what my answer is.

As I think the question is of much more general interest than the narrow scope of that Astronomy thread, I've started a Q&A one on it.

[Nereid]

And my answer?

"It depends" ... culturally, these things become real when they appear as such in textbooks.

Within the branch of science the concepts first originated, perhaps a more important question might be "what's the difference, between a concept that's useful in terms of helping theories to get sharper and better and reality?"

Or maybe it's easier to answer the negative question (when did phlogiston, N-rays, etc cease to be real?)? When a better - simpler, greater range, better explanatory power - theory came along to absorb or replace the thing, or when more and better observations and experimental results showed the concept had too little consistency.

[TheOncomingStorm]

Well I think these things become real when evidence is found to back the concepts either through experimentation or observation.

[Ken G]

They never become real-- they are always just models. Models are all we can do-- reality is something else. But this all depends on how one define's "real", so I think the actual question to ask is, when do these things become real for various choices of definition of that word?

[Kwalish Kid]

No scientists runs around merely believing in models. You can't make a bowl of cereal with just believing in models, let alone get on with the rest of your life.

[Mild mannered]

But this all depends on how one define's "real"

My thought exactly.

Not wishing to be too far off the intended topic, but it's always fascinated me where the edge of reality - or our perceived reality - lies.

I know my table is composed of a bunch of particles and energy and at a very small level has no real edge or surface but I can knock on it and hear and feel a response - also my particles remain seperate - they don't merge with the table. We are both real and seperate at a macro level but at the micro there is very little to distiguish us.

Where do particles become real? Where is the edge of reality - I have no clue. The images I see as I look around me are not "real" they are pictures created by my own brain's "simulation software" - for want of a better description - I accept what is see is real - mostly! - because I can interact with it - so can I intuitively accept whether electrons, photons, neutrinos, black holes, quarks, dark matter, and dark energy are "real" - no, not on a gut level if I'm honest - but can appreciate how useful they are as tools to calculate how things work and interact with each other.

Lastly - this is where science is - to me - two very different animals. Observation - based on reality as we see it - and theory trying to explain what we are seeing - theory without observation is blind - however useful a tool - backed up by observation I'd say it becomes "real" enough to accept.

Sorry if this was too long....

[George]

I have heard: "Reality bites". If a concept can literally bite us, it is really real. It is one thing to be told as a child to watch out for rattlesnakes, but when one stumbles into a ratllesnake's biting range, it is amzaing how this reality takes on enhanced meaning. [This represents the more extreme end for establishing reality.]

10% of our body's mass is hydrogen, IIRC, and the only "good" explanation is from BBT. This physical connection makes the theory more real than other theories such as Dark Matter theory. When I can throw some DM on my backyard grill, then it will be real. (Notice how it is always better when we are doing the biting rather than reality. )

[Ken G]

No scientists runs around merely believing in models. You can't make a bowl of cereal with just believing in models, let alone get on with the rest of your life.

I'm not interested in the "beliefs" of scientists, that is their own affair. I am talking about what we mean when we say "real". I can think of at least three fundamentally different meanings relevant to this thread:
1)scientific: reality is whatever we think it is that is consistently an effective model. Future models may be radically different from what we call "real", but what worked for us will continue to work-- the future models must encompass the present ones if they are "real".
2)philosophical: reality is whatever ideal concepts that we form that will never be improved on or replaced by more practiceable concepts, because they are the reality (of course this definition is the null set-- this is my point.)
3)existential: reality is whatever is that allows us to think about it, it is not our concepts about reality or models of reality.

[EDG]

I'm not interested in the "beliefs" of scientists, that is their own affair. I am talking about a meaningful definition of reality, and how lacking that is so far in this thread.

And that's your opinion. Personally, I'm not interested in philosophical navel-gazing about what is "real" or what is "truth". As far as I'm concerned, if it's observable then it's real, and if it's not then it isn't.

I thought these things are real anyway? We've detected all of them, we know they exist.

[Noclevername]

Things don't "become" real, they are real, and we learn to detect them. Or they aren't, like phlogiston, and we eventually figure out something else. It's an ongoing process of discovering what is real, not "making" anything real.

[Cougar]

They never become real-- they are always just models.

I side with Noclevername -- They were always real. Our models are just our attempts to characterize them, and I think in general our models have just gotten better and better.

"One can imagine a category of experiments that refute well-accepted theories, theories that have become part of the standard consensus of physics. Under this category I can find no examples whatever in the past one hundred years." -- Steven Weinberg

[kzb]

My feeling is that in this area of science, the theories and hypotheses are too far in advance of the concrete observations and experiment. I'm afraid black holes, dark matter and dark energy are still not real to me. I'm too skeptical.

As for neutrinos: they were thought necessary by nuclear physics to make reactions balance, and in the end they have been directly observed. So that ticks the boxes for me there. Quarks I have not taken any interest in.

[Ken G]

And that's your opinion.

Exactly what did I say that you could characterize as "opinion"? I stated facts. Please tell me what I said that is not a fact.

Personally, I'm not interested in philosophical navel-gazing about what is "real" or what is "truth". As far as I'm concerned, if it's observable then it's real, and if it's not then it isn't.

Then you are doing just what I asked-- offering a definition of "real". It is a very weak definition, because it changes as our observations change. We used to observe "particle trajectories" obeying Newton's "laws". That was quite real to the scientists of the day. We now know those were just models for how particles respond. Very good models, in the appropriate circumstances, but hardly "the reality". Have you not heard of quantum mechanics?

I thought these things are real anyway? We've detected all of them, we know they exist.

Now you must ask yourself just what we detected. Please be specific. I don't want your interpretations, I want what was detected.

[Ken G]

Things don't "become" real, they are real, and we learn to detect them.

So you think we detect "things" do you? Now, just how do we do that? We detect what our instruments tell us we are detecting-- the rest is mental construction. I'm just telling you the facts here.

Or they aren't, like phlogiston, and we eventually figure out something else. It's an ongoing process of discovering what is real, not "making" anything real.

What you are saying is that some models are quite good in some situations, and survive in those situations, and others are good essentially never, and are replaced. That's all one can say and still be doing science.

[Ken G]

"One can imagine a category of experiments that refute well-accepted theories, theories that have become part of the standard consensus of physics. Under this category I can find no examples whatever in the past one hundred years." -- Steven Weinberg

All Weinberg is saying here is that models that have worked well for something will always work well for that thing and things somewhat like it. It's not terribly profound, frankly. If you look outside the realm of what has been tested, we generally need new models-- what does that tell you?

[Gillianren]

So you think we detect "things" do you? Now, just how do we do that? We detect what our instruments tell us we are detecting-- the rest is mental construction. I'm just telling you the facts here.

Putting "this is a fact" after your opinion doesn't change the fact that it is, indeed, an opinion. Maybe I just don't understand what you're driving at, but it sounds like an opinion to me.

[Ken G]

Putting "this is a fact" after your opinion doesn't change the fact that it is, indeed, an opinion. Maybe I just don't understand what you're driving at, but it sounds like an opinion to me.

My statement that "we detect what our instruments tell us we are detecting, the rest is mental construction" is certainly a scientific fact. It is the simple result of observing that process. I claim it is important, when doing science, to distinguish what we are forced to conclude versus what we have simply chosen to conclude because we find it a useful model. That is part of science, we do it all the time. If my watch says it took a rock 5 seconds to fall, I am forced to conclude that the measurement is 5 seconds. But if I want to call the rock a particle, and say it followed a trajectory, that is a choice I have made. In point of fact, we know that a rock is not a particle, it is comprised of particles, none of which follow trajectories in any absolute sense. So the concept of a rock trajectory is a mental construct, and a very useful one. One must recognize the distinction between "reality" from mental constructions of same, or one is not listening to what science has told us. Of course we often choose, for expediency, not to make that distinction, but we must still recognize its existence.

[Noclevername]

What you are saying is that some models are quite good in some situations, and survive in those situations, and others are good essentially never, and are replaced. That's all one can say and still be doing science.

Some models are accurate and consistent with observations. Some models can stand up to the reality check of experimentation. Science is about finding and fine-tuning that accuracy.

[Ken G]

Some models are accurate and consistent with observations. Some models can stand up to the reality check of experimentation. Science is about finding and fine-tuning that accuracy.

I agree completely-- finally a statement of what science actually is! But also recognize that what we mean by "stand up to the reality check" of experimentation is subjective-- we decide what will constitute "standing up", according to our needs, not what is "real"-- unless we simply define the latter by the former (which some may be doing, and that's fine, I merely point out the need to recognize that definition, along with alternatives that other people might mean).

[EDG]

Now you must ask yourself just what we detected. Please be specific. I don't want your interpretations, I want what was detected.

This is exactly the sort of philosophical twaddle that I think is an utter waste of time.

We know that these things that were listed in the OP exist. We've detected them. That's all that matters.

[George]

What exists are the direct and indirect detections only. I've been burnt by photons and bit by electrons, but dark energy has yet to be near that real to me.

[Celestial Mechanic]

This is exactly the sort of philosophical twaddle that I think is an utter waste of time. We know that these things that were listed in the OP exist. We've detected them. That's all that matters.

I feel your frustration with philosophy. (My disdain for it is well-known here.) But I can also understand the uneasiness that many people feel because of the indirectness of the observations. Let me run down the list:

• Electrons -- directly through observation in bubble-chambers, electron diffraction experiments, etc.
• Photons -- directly through photoelectric effect.
• Neutrinos -- indirectly through inverse beta decays, but we've been able to create them at will in sufficient numbers to detect them.
• Quarks -- indirectly in particle accelerator experiments.
• Black holes -- indirectly through detection of accretion disks or movements of nearby stars.
• Dark Matter and Dark Energy -- indirectly by inferences from galactic rotation curves (DM) and cosmological arguments (DE).

The first four we have from laboratory experiments; black holes from astronomical observations; the evidence for DM and DE is of a very indirect kind that relies heavily on theory. I can understand the problems people have with it.

[George]

It's interesting that the BA has a new blog item entitled: "Do black holes really exist?". Technically, they don't (kinda, sorta). Certainly, there is something there that is real with these objects, but will better models come along and refine their realness?

[EDG]

What exists are the direct and indirect detections only. I've been burnt by photons and bit by electrons, but dark energy has yet to be near that real to me.

Yes, but the universe doesn't care whether anybody thinks something is real or not . Reality itself isn't subjective - things exist and carry on existing whether we believe in them (or are even aware of them) or not.

[EDG]

The first four we have from laboratory experiments; black holes from astronomical observations; the evidence for DM and DE is of a very indirect kind that relies heavily on theory. I can understand the problems people have with it.

DM has been detected by its gravitational influence on matter. So far it's really a temporary label, since we don't know exactly what it is, but we know it's there.

IIRC, DE is there to explain why the universe isn't expanding at the speed we think it should be. Again, it's a temporary label for a "fudge factor", but out of all of the things listed it's on the shakiest ground in terms of whether it is actually a physical reality or just a manifestation of the flaws in our current theories.

[trinitree88]

I think neutrinos were observed directly as neutral currents (Z⁰'s) with the observation of knock on electrons in liquid hydrogen bubble chambers. Gargamelle, C.E.R.N. circa 1979. Pete

[Ken G]

This is exactly the sort of philosophical twaddle that I think is an utter waste of time.

Then you know nothing at all about science, you only know the results of science. Fine, if all you care about are results, but science is more than what comes out the other end. (And "twaddle" is a foolish word, used by people who have no actual argument to make.)

We know that these things that were listed in the OP exist. We've detected them. That's all that matters.

If we detect something, then something is real-- we can agree there. If we want to associate our detection with a concept like "neutrino", more's the better. But it is a very different question when we ask "are neutrinos real". Still, it might not benefit you to understand that distinction, especially if you are not doing fundamental particle research (as most of us are not!), and have no interest in the meaning of knowledge.

[Ken G]

I've been burnt by photons and bit by electrons, but dark energy has yet to be near that real to me.

How do you know you've been burnt by "photons"? Photons are elementary excitations in a field theory. You've been burned by that? You've been burned by something, surely, but photons are mental constructs. It seems very likely to me that someday we will have a model that replaces photons, though of course the photon concept will continue to be useful.

[Ken G]

Yes, but the universe doesn't care whether anybody thinks something is real or not.

Agreed. It also doesn't care what we choose to label "photons".

[Noclevername]

Agreed. It also doesn't care what we choose to label "photons".

So according to you, nothing outside of your own head can ever be confirmed as real, it's just what you think your senses are telling your brain. So why not just imagine people agreeing with you, and leave the rest of us alone?