BB Theory vs. Theory of Evolution - which is more thrustworthy?

[CRGreathouse]

In my mind there's no question but that evolution is more reliable/well-known/etc. than big-bang theory. There are still questions about how evolution works, and cladistics is wide open, but the foundations are solid. We see a massive amount of evolution yearly, especially in viral reassortment; the fossil record allows us to see the same process on organisms with longer generations.

The Big Bang theory, on the other hand, is very much in development. While the basics are mostly agreed-upon, there are frequent revisions to our understanding of the finer points. It's not out of question that a major inconsistency in the theory would be found, prompting a more radical re-imagining.

I consider both sound theories, on better footing even than certain practical sciences (like psychology). By all accounts both are more widely accepted than certain speculative fields like abiogenesis and M-theory.

 

[matt.o]

Is the expansion of the universe an observed fact?

Yes, it is. But if you are meaning to imply that the expansion of the universe is the big bang, well...

The expansion of the universe implies a big bang but it is not the big bang. The big bang is a single event that happened a long time ago and cannot be directly observed. It is a prediction of a theory, not a fact.

I don't think I agree with this, russ_waters. The redshift of a galaxy is an observational fact. The explanation for this redshift is that it is due to the expansion of the Universe, which is a natural consequence of the standard cosmology, which is rooted in general relativity.

 

[D H]

The expansion of the universe implies a big bang but it is not the big bang. The big bang is a single event that happened a long time ago and cannot be directly observed. It is a prediction of a theory, not a fact.

I don't think I agree with this, russ_waters. The redshift of a galaxy is an observational fact. The explanation for this redshift is that it is due to the expansion of the Universe, which is a natural consequence of the standard cosmology, which is rooted in general relativity.

You are right that Russ is wrong in a sense, but not in the sense that you think. Russ is wrong in the sense that the expansion of the universe does not imply a big bang. What can be said is that the observed expansion of the universe (a scientific fact) is consistent with the big bang theory (a scientific theory). Scientific theories cannot be proven true. They can however be proven false. The observed expansion of the universe is inconsistent with the steady state model, which is why that model fell out of favor 40 years ago. The big bang theory makes a number of other predictions about what we should see in the universe. What we see so far is consistent with the big bang theory. Some future observation might well disprove the theory, or at least mandate a modification to it.

 

[matt.o]

You are right that Russ is wrong in a sense, but not in the sense that you think. Russ is wrong in the sense that the expansion of the universe does not imply a big bang. What can be said is that the observed expansion of the universe (a scientific fact) is consistent with the big bang theory (a scientific theory). Scientific theories cannot be proven true. They can however be proven false. The observed expansion of the universe is inconsistent with the steady state model, which is why that model fell out of favor 40 years ago. The big bang theory makes a number of other predictions about what we should see in the universe. What we see so far is consistent with the big bang theory. Some future observation might well disprove the theory, or at least mandate a modification to it.

Ah, I am right, but not in the sense you think! The problem is I neglected to remove the part you quoted form my quotes. The part I was objecting to was that russ_waters was agreeing that the expansion of the Universe was an observed fact, which it isn't. The redshift of a galaxy is an observed fact, as is its correlation with distance. The expansion of the Universe is an interpretation of the redshift (and redshift-distance relationship) based on GR.

 

[russ_watters]

You are right that Russ is wrong in a sense, but not in the sense that you think. Russ is wrong in the sense that the expansion of the universe does not imply a big bang. What can be said is that the observed expansion of the universe (a scientific fact) is consistent with the big bang theory (a scientific theory). Scientific theories cannot be proven true. They can however be proven false. The observed expansion of the universe is inconsistent with the steady state model, which is why that model fell out of favor 40 years ago. The big bang theory makes a number of other predictions about what we should see in the universe. What we see so far is consistent with the big bang theory. Some future observation might well disprove the theory, or at least mandate a modification to it.

Could you explain that a little more - I don't see how your explanation disagrees with the word "implies". It doesn't seem to me to address the usage of the word at all!

In any case, are you just quibbling with the historical order things happened? I'm a little thin on who did what and when (and the Wiki seems to contradict itself on the key part of the history...), but I don't see how this really matters. Taken completely by itself, expansion implies a big bang. Ie, if GR hadn't been formulated until decades later, we'd probably still have had a Big Bang theory in the 1930s due to Hubble's discovery alone.

 

[russ_watters]

Ah, I am right, but not in the sense you think! The problem is I neglected to remove the part you quoted form my quotes. The part I was objecting to was that russ_waters was agreeing that the expansion of the Universe was an observed fact, which it isn't. The redshift of a galaxy is an observed fact, as is its correlation with distance. The expansion of the Universe is an interpretation of the redshift (and redshift-distance relationship) based on GR.

Until such time as another viable cause of the observed redshift is found, the redshift can be regarded as the visual representation of the expansion. Your quibble is like quibbling that your eyes don't "see", a la Morpheus in The Matrix: 'reality is just electrical signals interpreted by your brain'. Scientists operate on the assumption that reality is as they see it, absent a good reason to believe that their senses and instruments are screwing with them.

 

[junglebeast]

I don't think I agree with this, russ_waters. The redshift of a galaxy is an observational fact. The explanation for this redshift is that it is due to the expansion of the Universe, which is a natural consequence of the standard cosmology, which is rooted in general relativity.

Indeed...and expansion of the universe is not the only thing that could cause the observation of a red shift.

 

[matt.o]

Until such time as another viable cause of the observed redshift is found, the redshift can be regarded as the visual representation of the expansion. Your quibble is like quibbling that your eyes don't "see", a la Morpheus in The Matrix: 'reality is just electrical signals interpreted by your brain'. Scientists operate on the assumption that reality is as they see it, absent a good reason to believe that their senses and instruments are screwing with them.

Sure, assume reality is as we see it, but we have never directly observed the expansion of the Universe. The expansion has been indirectly observed through the redshift-distance relation. This redshift-distance relation is observed fact, which provides supporting evidence for Universal expansion, which is not observed fact.

Aside from this, I have issues with the use of the word "fact" scientifically, since for its dictionary definition to be met requires something science is not really capable of. In any case, I won't digress further here.

 

[wildman]

That's theistic evolution, not creationism.

Creationism is God making the universe. Theistic evolution is saying that God made the universe using evolution. Theistic evolution is creationism. However as Russ said, how the word is normally used implies zapping things into being or direct involvement in making things run (Intelligent Design). Words are tricky...

 

[Moridin]

Creationism is God making the universe. Theistic evolution is saying that God made the universe using evolution. Theistic evolution is creationism. However as Russ said, how the word is normally used implies zapping things into being or direct involvement in making things run (Intelligent Design). Words are tricky...

Maybe they are tricky for you, but I experience no such thing.

Creationism is the position that the general principle evolution, specifically, universal common descent, has not occurred, but that special creation, that is, a god producing all biological organisms in their present form is factual and that there are empirical evidence to support this. Theistic evolution (the position that a god only set the initial conditions or intervenes from time to time) is thus not a form of creationism. For instance, Ken Miller (cell biologist), Francis Collins (geneticist), Fransisco J. Ayala (geneticist) are theistic evolutionists, but not creationists.

This is the description that both creationists, theistic evolutionists and materialists routinely use when talking about these issues. It is clear for everyone who has any experience with these issues. You can, of course, arbitrarily relax the definition if you want, but then we might as well call engineering or computer programming a form of creationism and lump these professions with Answers In Genesis, Institute for Creation Research or the Discovery Institute. Calling theistic evolutionism creationism makes the same mistake as creationists calling theistic evolutionism a form of atheism; it is simply a contradiction in terms.

 

[russ_watters]

Indeed...and expansion of the universe is not the only thing that could cause the observation of a red shift.

Can you substantiate that assertion? I don't know of any proposed alternate mechanism currently considered viable by mainstream scientists.

 

[russ_watters]

Sure, assume reality is as we see it, but we have never directly observed the expansion of the Universe.

In that case, we've never directly observed anything. I don't find this quibble useful.

Aside from this, I have issues with the use of the word "fact" scientifically, since for its dictionary definition to be met requires something science is not really capable of. In any case, I won't digress further here.

Science certainly deals in facts. What I didn't say, but you should still assume I meant is that all facts in science have error bars associated with them.

I am not elevating science beyond what it is - please don't assume I am as a result of me not including every conceivable caveat to every statement I make.

 

[russ_watters]

Creationism is God making the universe. Theistic evolution is saying that God made the universe using evolution. Theistic evolution is creationism. However as Russ said, how the word is normally used implies zapping things into being or direct involvement in making things run (Intelligent Design). Words are tricky...

The overwealmingly predominant usage of the word "creationism" is to describe strict, biblical creationims. If someone uses the word "creationism" and doesn't specify one of those minor, special cases, that is what they should be assumed to be talking about. There is no need to quibble/weasel about this. It is creating a conflict that doesn't really exist...

...unless the person doing so is doing it to be intentionally coy about creationism. Crackpots play such word games all the time. But there is also no good reason to engage crackpots on their own turf/by their rules.

 

[matt.o]

In that case, we've never directly observed anything. I don't find this quibble useful.

No, you are missing the point. Even in your idealistic world where every measured phenomenon is taken as what is reality, we still haven't directly observed the Universe expanding. No-one has ever directly observed the distance of an object changing with time due to expansion! The observational fact here is the redshift-distance relation. I don't know how else I can put it. I am not arguing for some alternative explanation for the redshift-distance relation, but it is sending the wrong message to mix up the interpretation of the observations with the observations themselves.

Science certainly deals in facts. What I didn't say, but you should still assume I meant is that all facts in science have error bars associated with them.

No, not in the dictionary sense of the word. Science deals with corroborating evidence and disproving alternate theories. The word "fact" only needs to be used in science to keep the ignorant at bay, i.e., those that don't understand how science works and think that by not using strong words like "fact" scientists know less than they do.

I am not elevating science beyond what it is - please don't assume I am as a result of me not including every conceivable caveat to every statement I make.

No, you are mixing theory/interpretation and observation, though. My rebuttal to what you said regarding the Universal expansion being observed fact was not a caveat, I was pointing out that what you said was actually wrong.

 

[junglebeast]

Can you substantiate that assertion? I don't know of any proposed alternate mechanism currently considered viable by mainstream scientists.

First of all, inflation theory involves a made up new force that causes inflation, and the only evidence for said force is the so called inflation itself. But the inflation isn't even a direct observation -- it's an induction based on other inductions based on other inductions...and most of those inductions have observations which are contradictory!

Second, what scientists currently believe is of no bearing on the fundamental difference between observation and induction. The red shift is an observation. Inflation of the universe is a theory born of great leaps in inductive reasoning. Inductive reasoning is a flawed form of reasoning that is not mathematically valid. See the http://en.wikipedia.org/wiki/Problem_of_induction" .

One of the assumptions in the model for inflation of the universe is the cosmological principle -- "http://en.wikipedia.org/wiki/Cosmological_principle" " . This principle is essentially a way to state formally, "we have no friggin clue, but we're going to pretend like we do in the absence of something better." Oh, and it isn't even validated by observations (see the bottom of that page for some of the contradictory observations).

You can choose to believe in inflation if you want. It may be the most likely theory we have. But that doesn't make it a fact. The only evidence for it is based on flaky induction, extrapolation and wild guesses.

Anyway, you want to know other possible reasons why we might observe a red shift? Here are a couple,

1) Observable mass is expanding through spacetime (as opposed to spacetime itself expanding)
2) Time could move slower in the presence of mass

I don't need evidence for these things to prove my point. Rather, the burden of proof is on the person who claims that it's a fact and that there are no other possible alternative explanations.

 

[matt.o]

Uh, inflation and expansion are two separate issues. We are discussing the latter.

 

[BoomBoom]

The expansion has been indirectly observed through the redshift-distance relation. This redshift-distance relation is observed fact, which provides supporting evidence for Universal expansion, which is not observed fact.

I would agree with this, but aren't other sources of evidence to be considered as well, such as angular size and luminosity?

 

[matt.o]

I would agree with this, but aren't other sources of evidence to be considered as well, such as angular size and luminosity?

Yes, there are more lines of evidence supporting the expansion. That is why it has been so (almost) universally accepted as the explanation of the redshift-distance relation. One particular example is the Tolman surface brightness test, which predicts that surface brightness should go as (1+z)^4 in an expanding Universe. This is not quite what is measured, but the difference is simply due to luminosity evolution of galaxies.

 

[CRGreathouse]

The overwealmingly predominant usage of the word "creationism" is to describe strict, biblical creationims. If someone uses the word "creationism" and doesn't specify one of those minor, special cases, that is what they should be assumed to be talking about.

I don't think so. wildman's assertion matches my understanding and experience in speaking with people.

 

[russ_watters]

No, you are missing the point. Even in your idealistic world where every measured phenomenon is taken as what is reality, we still haven't directly observed the Universe expanding. No-one has ever directly observed the distance of an object changing with time due to expansion!

I don't understsand: now it sounds like you are saying that even if redshift is taken at face value, we still haven't observed motion. But taking redshift at face value means motion. That's what redshift is! It is a direct measurement of a distance change over an interval of time.

The observational fact here is the redshift-distance relation.

Forget the redshift-distance relation for the time being (and yes, I know I mentioned Hubble) and consider redshift alone, without distance ever being measured. Even if we don't ever measure a distance, but only know we see redshift everywhere, that's seeing that nearly every galaxy is moving away from us, just as plainly as your eyes tell you that a car is moving away from you, even if you can't actually quantify the distance. Almost every galaxy moving away from us = expansion.

No, not in the dictionary sense of the word. Science deals with corroborating evidence and disproving alternate theories. The word "fact" only needs to be used in science to keep the ignorant at bay, i.e., those that don't understand how science works and think that by not using strong words like "fact" scientists know less than they do.

I don't see an explanation there, just a claim. I can't comment on it if you don't explain yourself, so I stand by my interpretation.

It does seem, though, that you are claiming the dictionary definition of the word "fact" does not allow for error bars, as required by science. That's just not true. The dictionary definition even includes a direct reference to scientific data collection!: http://dictionary.reference.com/browse/fact

Ie, the word "fact" is a direct synonym for the word "data".

 

[russ_watters]

I don't think so. wildman's assertion matches my understanding and experience in speaking with people.

I sometimes hate being the forum pedant, but again I feel compelled to go to the dictionary:

1. the doctrine that matter and all things were created, substantially as they now exist, by an omnipotent Creator, and not gradually evolved or developed.
2. (sometimes initial capital letter) the doctrine that the true story of the creation of the universe is as it is recounted in the Bible, esp. in the first chapter of Genesis.
3. the doctrine that God immediately creates out of nothing a new human soul for each individual born.

http://dictionary.reference.com/browse/creationism

Like I said, recently it seems to me that there has been a lot of attempted weaseling about this definition. But the way the definition reads, there is no wiggle room.

So let me be more general: if someone uses a word - any word - without caveat, you should assume they are using the word as it is defined in the dictionary.

 

[matt.o]

I don't understsand: now it sounds like you are saying that even if redshift is taken at face value, we still haven't observed motion. But taking redshift at face value means motion. That's what redshift is! It is a direct measurement of a distance change over an interval of time.

No, actually redshift is an observed shift in wavelength from some known value. It does not necessarily mean motion -- ever heard of gravitational redshift?

Forget the redshift-distance relation for the time being (and yes, I know I mentioned Hubble) and consider redshift alone, without distance ever being measured. Even if we don't ever measure a distance, but only know we see redshift everywhere, that's seeing that nearly every galaxy is moving away from us, just as plainly as your eyes tell you that a car is moving away from you, even if you can't actually quantify the distance. Almost every galaxy moving away from us = expansion.

This does not make expansion an observational fact! It is still an interpretation of the observational fact, which is redshift!

I don't see an explanation there, just a claim. I can't comment on it if you don't explain yourself, so I stand by my interpretation.

I was taking the more literal meaning of "fact", i.e, some absolute truth. This what people expect from science if they are to believe it.

Ie, the word "fact" is a direct synonym for the word "data".

I agree with this outside of quantum mechanics and depending on how you define "data", however the expansion is not the data here, the redshift-distance relation is, thus the redshift-distance relationsip is the observational fact, not the expansion.