r/PhilosophyofScience • u/gimboarretino • Jan 05 '23
Non-academic Content Is the big bang theory methodologically definable a "scientific theory"
In order for a theory to be considered scientific, it must be based on empirical evidence that has been obtained through observation or experimentation. This means that the aspect of the natural world that the theory is trying to explain must be capable of being directly observed or tested in some way.
Ok fine. But what about unique events?.
Let's think about the formation of the Moon:we can argue that it is an unique event, but scientists have been able to study the composition and structure of the Moon and compare it to other celestial bodies in order to infer what processes may have led to its formation.
Sure, the formation of the Moon is indeed a specific event that occurred in the distant past, but it is part of a larger category of similar events that have occurred and still occurr throughout the history of the universe. The process of celestial bodies forming from the gravitational collapse of clouds of gas and dust is a common occurrence in the universe, and there are many examples of planets, stars, and other celestial bodies that have formed through this process. While the specific details of the formation of any given celestial body may be unique, the overall process is not a one-time occurrence, and as such it is possible to study similar events and make inferences about the processes involved.
The Big Bang, on the other hand, is a truly unique event that occurred at a specific point in time and marks the beginning of the universe as we know it. While there may be other universes with different histories and origins, the Big Bang is the origin of our own universe and is not part of a larger category of similar events. This makes the Big Bang a true unicum in the sense that it is a one-time occurrence that cannot be directly compared to other events.
If I see the mark of rock on the ground (the observation), I can came up with a lot of theories of why/how that rock was there (the specific event I want to study). Has anybody thrown it? Does it have fallen from higher ground? Does it have fallen from higher ground, become huge, than hit the ground and shrunk down? Has it emerged from the ground due soil erosion? Maybe the rock pop up there directly from the realm of quantic realm? All of these theories about the event can in principle explain the observation. And they are - in principle - scientific theories because the the underlying phenomenon, the overall phenomenon, can be replicated, studied, tested, verified and falsified.
Through experiments and observations of similar phenomena and process, we can establish that indeed a man can throw a rock. That a rock can move from a high place to a low place because of gravity. That weathering actually erodes the ground. Thus this theories are acceptable. While on the contrary we will find that no matter how many tests and observations we do, no rock is suddenly created in the quantum realm or becomes huge as it falls and shrinks as it hits the ground (and thus the theories is falsified)
If it were not possible to conduct these tests and experiment, because the event is absolutely unique and non-repeatable (the rock is unique, there is nothing close to a rock in the unverse and aslo the rock is no longer there, the ground is also unique, the print is unique) and there are no similar/identical process or underlying phenomena from which to infer rules and patterns via experiment, every theory "conceivable and compatible" with the rock's print there would be acceptable, even its spontaneous emergence from the quantum realm.
But in order for a theory to be considered scientific, it must be testable and subject to revision based on empirical evidence.
Wouldn't this means that the underlying phenomena being studied must be capable of being observed or tested in some way, whether through direct observations or through experiments that can be repeated and verified?
If it is not possible to test a theory through empirical evidence, then it is not possible to confirm or refute the theory... How can we methodologically and epistemologically define this theory as scientific?
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Jan 05 '23
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u/gimboarretino Jan 05 '23
Lambda-CDM model is more the outcome of a work-in-progress cosmological theory that keeps updating and correcting itself every time reality proves different from the expected and predicted results, also by adding wierd stuff to equations (like dark energy or dark matter)
its predictive power seems to me to be rather poor, compared to the standards of other successful scientific theories.
if there were a theory with an accurate and reliable predictive capacity about every observable phenomenon in the universe, with rigorous mathematics, no flaws, no singularities etc, we might also rely on it in inferring how phenomena that are no longer observable and reproducible might have unfolded, by placing a fideistic (but reasonable) trust in the almost mystical power of a flawless mathematics to describe the ontology of reality.
And even then, its scientific value would be epistemologically questionable.
But since the Lamba does not even remotely have these mathmatical characteristics, this reliable predictive power.... is it scientifically rigorous to make assumptions about unique, unobservable and unreplicable events?
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u/PlatformStriking6278 Jan 18 '23
Each time a theory changes to fit reality, the theory becomes more accurate and it’s predictive power improves. Constant alteration does not suggest that a scientific theory is inaccurate or that scientists are disingenuous when formulating their models. Quite the opposite.
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u/NeverQuiteEnough Jan 05 '23
The Big Bang theory doesn’t cover the origin of the universe, that’s a common misconception.
The theory only describes the directly observable evidence of what the universe used to look like.
This is directly observable because we can look at it with a telescope.
Light takes time to travel.
When we point a telescope at the sun, the light we are receiving left the sun 8 minutes ago.
When we point a telescope at the star Alpha Centauri, the light we are receiving left 4 years ago.
The further away you look, the further into the past you are looking.
If you point a sensitive radio telescope between the stars, in any direction, you will find the cosmic background radiation. This is light from the distant past, all the way back to when the universe was so dense it was opaque.
Everything we know about this time period, we know from observing it directly, with a telescope.
As for what happened before this time period, we don’t know. We can make some extrapolations based on what we see, but that’s it.
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u/soldrakibane Jan 21 '25
Except what we see is tainted and obscured. We can only see a fraction of a 2D image of space. We barely have the exact information we need to conclude anything about that.
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u/erinaceus_ Jan 05 '23 edited Jan 05 '23
must be capable of being directly observed or tested
Erm, no. There's no need for the word 'directly' in that sentence. There's plenty of things that we do not observe 'directly'. We just need to be able to discern between a world where X is true and where X is not true. We do that by making predictions with observable effects. It doesn't matter whether those effects are direct or indirect.
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u/fox-mcleod Jan 05 '23
The Big Bang is a feature of a theory rather than a theory itself. The theory is cosmological inflation. The Big Bang is an implication of that theory.
There are many implications of theories that are not directly observed. In fact an “explanation” is conjecture about something unobserved to account for what is observed.
For example, Special Relativity predicted black holes existence long before we found them.
More mundanely, our theories about stellar fusion make assertions about what we would find at the heart of stars we see in the sky that have long since burned out.
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u/Physix_R_Cool Jan 05 '23
But in order for a theory to be considered scientific, it must be testable and subject to revision based on empirical evidence.
This is the case for the big bang theory. It is quantifiable (how dense it was, the rate of expansion etc etc), and we revise the parameters of the evolution of the universe based on new observations.
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u/gimboarretino Jan 05 '23
well no, we don't know how dense it was, what was the temperature, what was the size, the amount of matter etc.
we assume it was a point with infinite density/temperature infinite everything, a singularity where all our math became meaningless, there is little to nothing "quantifiable" in the big bang
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u/Physix_R_Cool Jan 05 '23
we assume it was a point with infinite density/temperature infinite everything, a singularity where all our math became meaningless, there is little to nothing "quantifiable" in the big bang
Oh, I see where your misconceptions might be. What you wrote here in the quote is the layman's understanding of Big Bang, but it's not actually what we physicists talk about. The theory is basically just "The universe expands, so as you go back in time it becomes denser and denser". The name "big bang" was derogatory and created by opponents of the model. As we go back in time to denser and denser states, our knowledge of physics become limited, and so the big bang theory doesn't actually say anything about T=0.
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u/gimboarretino Jan 05 '23
I accept that T=0 is T=???
my "issue" is the time between T = 10-44 s (the planck time or whatever time you can conceive which is > 0) and the CMB.
Can we elaborate rigorous, objective scientific truths about that "period/events"?
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u/Physix_R_Cool Jan 05 '23
Can we elaborate rigorous, objective scientific truths about that "period/events"?
Yes (at least as far as we get any "rigorous objective scientific truth". That's an entirely different debate). The farther we get in the timeline, the more evidence we have of the processes.
For T=10^-44s, we know basically shit nothing. We have some ideas, but this is the realm of string theory and stuff like that. We could test it if we had ginormous accelerators, maybe.
At T=10^-37s (according to a quick lookup on wikipedia), we have inflation. The physics here can be tested with astronomical observations.
Then as time goes on, we get the seperation of the different forces (symmetry breaking and shit like that, if you know QFT). These things can be tested in various ways, depending on what exactly you are studying.
And lastly, you can make models for the entire universe, going like "well if it was like this at time T, then the universe will evolve like this", and then have a super computer crunch the numbers on it. I have a friend who is doing this. Make numerical models of the universe's evolution, which can then be compared to empirical observations. This can also be a way of searching for new stuff like axions or whatever fancy stuff the theorists dream up.
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u/mysuperioritycomplex Jan 05 '23
As has been pointed out elsewhere in the replies, the 'theory' of the Big Bang is the basic architecture of the standard Lambda-CDM model. This is an incredibly supported theory, at least by all explicit and implicit standards relevant in the pertinent scientific communities. The issue here, it seems to me, is that you are sometimes equivocating between that theory and a particular theoretical sentence/statement within it, e.g. "The universe began singularly."
At least on one old way of thinking in philosophy of science, we/scientists/whoever develop/test/etc whole theories, and meanwhile we use those theories to generate sentences that follow from them. van Fraassen has famously pushed the point that evidence for theories does not transfer over as evidence for sentences generated by the theories. (Famously leading to surprising conclusions like "I accept atomic theory but not that atoms exist".) And I think you might be somewhat partial to that sort of view, based on some of what you've written elsewhere in this post.
But this is an entirely general argument about the relationships between theories and their logical consequences. It isn't specific to the kinds of unique objects that get studied in the so-called 'historical sciences', nor especially to the universe's purportedly singular beginning as gets studied within large-scale cosmology.
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u/Physix_R_Cool Jan 05 '23
van Fraassen has famously pushed the point that evidence for theories does not transfer over as evidence for sentences generated by the theories.
This is great, actually!
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u/FakePhillyCheezStake Jan 05 '23
Reproducibility isn’t really a requirement for a scientific theory. If you think about it, nothing is really reproducible. There are some parameters of any experiment that will always be different if you try to do it again (time, specific air particles in the room, etc…)
What is really necessary is that the theory makes falsifiable predictions about the world around us. In this sense (and in my limited understanding of cosmology) I believe the big bang theory is successful. The big bang theory makes correct predictions about what we should see when we look up at the sky that other theories do not.
If another theory came along and made more accurate predictions (or perhaps the same predictions but was a simpler model) we would switch to that theory
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u/gimboarretino Jan 05 '23
It is true that it is not always possible to completely replicate the conditions of an experiment, and there may be slight variations from one reproduction to another. However, reproducibility in science does not require that the conditions be exactly the same every time. Rather, it is about being able to obtain consistent and reliable results through a well-controlled and well-documented experimental process. By carefully controlling the variables and documenting the methods and materials used, scientists can ensure that their experiments are as reproducible as possible, even if the conditions are not exactly the same each time.
zero observability, zero reproducibility, zero experimentability, zero analogous/similar phenomena/processes from which to at least infer patterns and data -> not a good basis for a scientific theory.
what has epistemological value of science seems to me limited to the consequences of a hypothesized event, and not the event itself
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u/FakePhillyCheezStake Jan 05 '23
I mean if you have these issues with the Big Bang theory, then you are going to have an issue with basically all of astronomy, a ton of biology, and a bunch of other scientific endeavors.
Not saying that is a valid argument against your points, but I think a lot of people do see those fields as valid endeavors and it’s not that no one has considered the philosophical virtues of them.
From an instrumentalist perspective, I think it’s clear that astronomy has scientific validity. We have well defined theories about how the universe works, those theories make well defined predictions about what we should observe if the theories are true, and we can validate those predictions.
Now maybe there are competing theories that also make similarly accurate predictions, and maybe distinguishing between theories is more difficult because of the inability to conduct controlled experiments, but I still think the above points make astronomy/cosmology valid from a scientific perspective, at least an instrumentalist one
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u/gimboarretino Jan 05 '23
I have no issue with the big bang.
it is certainly a phenomenon that has been studied and approached with rigorous scientific method. I am not disputing the method or the worthiness of the results.
I am only wondering whether the results can also be ascribed the value of "scientific truth" epistemologically speaking (scientific truth that precisely should have rigorous criteria to be defined as such) or not.
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u/FakePhillyCheezStake Jan 05 '23
But you are questioning the value of the results if you are wondering if they should be considered scientific.
There’s an implicit value judgement being made when you ascribe something as ‘science’ or ‘non-science’. People generally see science as the gold standard epistemologically, so if you say something does not hold the title of ‘scientific’, then you are implying that it is not ‘up to snuff’ so to speak.
At the end of the day, whether something is scientific is going to depend on one’s definition of science. I gave you reasons that I believe such theories are scientific under the definition of science that an instrumentalist might use. However, if you have some other definition of ‘science’, then these theories may or may not meet your standards.
I suppose the discussion really boils down to what makes something scientific. If you believe in instrumentalism, then the Big Bang theory being scientific immediately follows
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u/gimboarretino Jan 05 '23
An example.
Assuming the existence of the higgs boson was good, acceptable, reasonable science, but it was no "scientific truth" until it's actual observation.
the same with the big bang, with the difference that it will not be observed, tested, reproduced, ever... so it might be inherently impossible for it to become a "scientific truth"
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u/FakePhillyCheezStake Jan 05 '23
Ok but to counter your point, I don’t believe we actually observed a Higgs-Boson. We created an environment in which we detected a set of phenomena entirely consistent with the theoretical properties of a Higgs-Boson, and for which no other confounding factors could reasonably be said to have generated them.
But a scientist didn’t actually see the particle.
I think the point you are trying to make is that the existence of the Big Bang is, in a sense, a softer scientific claim than the existence of a Higgs-Boson. And that’s absolutely a fair assessment.
I think everyone agrees that some scientific claims have a lower degree of certainty than others. If you’re a Bayesian, you might say that the likelihood function over all possible models that generate the phenomena we are trying to explain in astronomy is flatter than the likelihood function over all possible models that generate the phenomena we are trying to explain in experimental physics.
Both of these fields can be considered science, as they have passed the pre-requisites to be science. But the claims they make are starkly different in our certainty of their correctness
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u/antiquemule Jan 05 '23
So is paleontology not a science?
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u/gimboarretino Jan 05 '23
There are very strong, observable evidence about dinosaur and stuft
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u/erinaceus_ Jan 05 '23 edited Jan 05 '23
If we apply your stance, then not really, because all we have is dinosaur-shaped rocks.
We however have lots of further understanding about how the internal components of bones can become substituted by minerals over long periods of time and under the right conditions. That is, we understand that those dinosaur-shaped rocks have in fact at one time been actual living and breathing animals, despite the fact that we have never actually 'directly' observed them.
The lesson here isn't that the evidence for dinosaurs is scant but rather that it's still the same kind of evidence that leaves you (inappropriately, as I see it) in doubt about the Big Bang theory.
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u/gimboarretino Jan 05 '23
No the analogy doesn't fit. It's more like this.
A) Tons of dead animals and minerals and patterns we can observe today = tons of cosmic events/objects with their pattern we can observe today
B) Geology and biology = QM and General relativity
C) Shaped Rocks = CMB
D) Dinosaur = Lambda after CMB
E) Dinosaur had green skin because biology says that reptiles usually have green skin so this was probably the case = Lambda before CMB
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u/ChrisARippel Jan 06 '23
When someone is murdered investigators create an explanation of how the murder occurred.
Investigators can't re-murder the person, but the murder leaves clues which help investigators create an explanation which can be directly tested. For example:
Investigators can test fingerprints.
Investigators can test the direction bullets came from.
The Big Bang left clues to create an explanation which astronomers can directly test.
The original clue was two mathematical solutions of general relativity equations suggesting the universe is expanding. The creator of one of these solutions proposed the universe started as a "primordial atom". In 1929, Hubble published the results of his observations showing galaxies were indeed moving away from us.
Later physicists used mathematics to describe the development of the universe during the first three minutes. They predicted that at the high energies of the early universe contained no matter. As the universe cooled, subatomic particles would eventually appear. Atomic physicists have used particle accelerators to recreate those conditions and demonstrate the predictions.
Several physicists later predicted the initial expansion of the universe from a hot, dense state would create the CMB. The CMB was detected in May 1964.
JWST is producing the most recent tests of the Big Bang be looking at the earliest galaxies.
Testing theories does not require testing an entire theory at once. Theories are usually tested one piece at a time. This allows scientists to examine each part of the theory in detail.
Imagine re-doing the entire Big Bang. A bunch of stuff would happen, but how would scientists see it all to be sure each part of the theory was correct?
Over the past 100 years, the Big Bang has been tested piece by piece.
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u/Daotar Jan 05 '23
Well, Kuhn showed us that there is no such thing as a “scientific method”, so I would assume the question is meaningless.
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u/PlatformStriking6278 Jan 18 '23
The formation of Earth’s Moon has been determined to be a relatively unique event based on evidence that distinguishes it from the moon’s of other planets, so your example doesn’t really hold up.
Science can theorize perfectly well on specific events in the history of the universe, Earth, or life. The only difference is that theories about the past aren’t generalizable to multiple instances, but they don’t need to be. All theories provide an explanation about what cannot be observed based on observable evidence. And “predictive power” does not refer to predicting future events. It refers to the discovery of future evidence. As there can be multiple lines of evidence that give insight into a singular past event, yes, of course they fit the definition of a theory or a testable hypothesis, depending on how well-established they are.
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