I just found a critique by Ethan Siegel implying that there is some flaw in my article explaining Big Bang’s lack of an adequate scientific definition and hypothesis (titled “International Astronomical Union has no Definition for Big Bang“).
While flattering (I’ve made mistakes before and far prefer to get them corrected quickly), the critique fails to identify any flaws in my article and contains a number of incorrect or misleading assertions — including the false claim that the complete quote by Professor Peebles is somehow out of context.
It also spends most of its extensive effort with an elaborate distraction where it tries but falls short of describing a complete hypothesis for Big Bang. Since the article is copied on other blogs, its errors need correcting. So, here are some responses to the dispute article’s ideas and quotes.
First, I must give Mr. Siegel my special appreciation for using the correct term “Big Bang” and not employing the popular but misleading term “Big Bang Theory” since there is no such thing in astrophysics (though there are several dozen Big Bang Models). His article also does a marvelous job using wonderful graphics to help explain the “standard model” in general. So, on to the corrections.
1. Myth: The quote from Professor Peebles is out of context.
(“. . . quotes — out of context — famed cosmologist Jim Peebles.”)
1. Truth: The entire quote from Professor Peebles is provided. It is hard to imagine how a complete quote is out of context. In fact, it is harder to imagine how this quote could be more in context. Here, again, is the entire text of Professor Peebles quote:
“The name Big Bang is a very poor choice because it suggests a moment of time — a bang — and maybe also a place — where the bang occurred. Neither is part of the reasonably well tested theory of the evolution of the universe from a hot dense state to what we see around us. But the name has stuck, so I have stopped boycotting it.”
“As you see the definition is a mess. The connotation to me is the relativistic theory of the expansion of the universe.”
The context of the quote is a response to my asking —
“In searching for a definitive definition of ‘Big Bang’ I’ve asked IAU’s Cosmology commission. I received back a gracious confirmation from VP Brian Schmidt that IAU maintains no definition of “‘Big Bang.'”
“Do you have such a definition – or could you please direct me to one?”
While one may disagree with what Professor Peebles wrote, that is his full quote, in context – and with permission.
I respectfully suggest that Mr. Siegel needs to furnish some sort of explanation or correct, and issue a correction to, that incorrect claim. (Update: Mr Siegel did correct this error.)
2. Myth: The problem the original article has with Big Bang is that there is no “universally agreed-upon definition.”
2. Truth: While partially correct, that wholly sidesteps and ignores the focus and most important facet of my article which is Big Bang’s ambiguity. The complete quote from the article, which is from my published paper, is
“As of 2009 we have no agreed upon unambiguous, testable definition of Big Bang or Inflation models.”
The key part is ambiguity – not agreement. It is Big Bang’s ambiguity that prevents it from becoming an unambiguous scientific hypothesis. It really doesn’t matter if there is agreement on a definition – until after at least one complete hypothesis is established for Big Bang.
(The hypothesis requirement is not limited to Big Bang, it applies equally to every Cosmology idea, including the dozens if not hundreds, of non-Big Bang proposals including Steady-State, Plasma Universe, and Static Universe and each of their individual components. Nor is the hypothesis requirement limited to astrophysics; it applies to every experiment wanting scientific rigor.)
(Update: Mr Siegel has not yet corrected this error.)
3. Myth: My (Mr. Siegel’s) definition of Big Bang answers all questions. (This is not a quote, it is the theme of the article.)
3. Truth: Mr. Siegel’s article makes a beautiful start, as I noted – a marvelous job using wonderful graphics to help explain the “standard model” in general, but it ends up no more complete than any other Big Bang definition I’ve found.
As I try to gently remind Science Fair students, no one, not even Einstein or Newton, gets the luxury of describing only those parts of the experiment they want to – we must clearly describe all possible variables that could affect our results.
To help with that, here is a blank “Physical Cosmology Hypothesis Application Form” with simple straightforward questions (most are “Yes or No”) that any cosmologist can answer. No elaborate descriptions or graphics are needed.
If Mr. Siegel or anyone else would like to complete one, I and many others would be delighted to review it and to publish it. Besides the blank form, to help get started there are partially filled-in forms for LCDM and Static Universe concepts.
(Update: Mr Siegel has not yet acknowledged the theme of my article is Big Bang’s ambiguity, nor his diversion or logical fallacy.)
4. Myth: Here’s a dazzling set of evidence and explanations that we know are true – so there’s no problem. (This is not a quote, but this fills the bulk of the article.)
4a. Truth: Evidence is no substitute for a Hypothesis.
Discussing evidence, even a truckload of dazzling evidence, before one provides a hypothesis is a logical fallacy called a distraction, sometimes referred to as a “Red herring”.
A complete Hypothesis is needed first so that everyone agrees upon what is being discussed. Only then is it proper to examine and debate evidence – otherwise the conjecture could be accused of having “moving goal posts.” To my knowledge, none of the several dozen Big Bang models have yet provided a complete Hypothesis as of June 2011.
“To debate evidence before a scientific concept has a clear, meaningful, unambiguous definition — is the equivalent of ‘putting the cart before the horse.’”
(Update: Mr Siegel has not yet acknowledged his diversion or logical fallacy.)
4b. Truth: While astrophysics has many undisputed findings, I have found a dispute for every idea in Cosmology. Every individual cosmology concept (on all sides of the Big Bang debate) is disputed by reasonable people employing seemingly sensible rationale.
So any claim that “we know” cosmology claim X,Y or Z is true, solidly or indisputably true, is probably wrong. How well we understand most cosmology principles is dramatically less solid than how well we understand gravity. We really don’t know much cosmology with certainty.
(Update: Mr Siegel has not yet corrected this error.)
5. Correction: Conventional definitions (even though incomplete) have Inflation occurring after Big Bang begins.
(Update: Mr Siegel strongly argues that his version is correct.)
(Though there are at least half a dozen versions of Inflation, anyone could easily create yet another conjecture that has Inflation occurring before Big Bang. While he may wish to argue this point of view, this just helps dramatize how ambiguous a “moving target” Big Bang’s incomplete definition is – and why unambiguous, clear and stable definitions and hypotheses are needed.)
Hypotheses are Helpful, Not Just Mandatory
Providing a complete and stable scientific hypothesis is not something to fear — it is something that gives an agreed upon starting point, accountability, rigor, repeatability and credibility to experiments and confidence to experimenters.
It remains my opinion, that until at least one Big Bang conjecture answers all the questions on the Physical Cosmology Hypothesis Application Form – it remains too ambiguous to satisfy the minimum criteria for an unambiguous hypothesis – let alone a theory.
However, I also look forward to having my mind changed when I get to review completed Physical Cosmology Hypothesis Application Forms.
Update July 20, 2011: Mr. Siegel corrected his article’s false claim that Professor Peebles quote was “out-of-context.” The critique still entirely misses the most important point of Ambiguity; the idea that “currently Big Bang is too ambiguous to be a scientific hypothesis.” Instead it uses a Straw man logical fallacy to dispute a trivial issue – that there is no consensus on a Big Bang definition.