I had been anticipating the biggest null result in science in the last century, perhaps ever, to be announced sometime this year, when just under ten days ago this paper came out: Observation of Gravitational Waves from a Binary Black Hole Merger. LIGO, the U.S. gravitational wave observatory, has received signals from what appears to be the merger of two black holes. What would have been the null result of the century has turned out to be the result of the century.
There’s a bit of a rehabilitation of Aristotle going on lately (Edward Feser is the one doing it that I’m most familiar with), and one of the things you’ll hear if you read that stuff is that we can reject Aristotle’s physics without rejecting his metaphysics. Surely we are more clever at physics than he was — right? Well, as it turns out, not exactly. Here’s a recent paper by a physicist showing that Aristotle’s physics is to Newton’s physics as Newton’s is to Einstein’s. In other words, it was (and is) perfectly rigorous in its domain of validity. The most obvious example he cites is of objects falling under the influence of gravity. In his famous experiment on the leaning tower of Pisa, Galileo showed that objects fall at the same speed, independent of their size and composition. Aristotle made the opposite claim, and what could he have been thinking? The short answer is that Aristotle’s result holds in the presence of a medium, such as air or water, and Galileo’s result holds in the absence of such a medium (or on short enough time scales that the medium doesn’t matter; if you repeat Galileo’s experiment from an airplane, you will come to Aristotle’s conclusions). There you go, the rehabilitation is complete. Aristotle wasn’t a moron.
I told you we scientists are good at predicting things. My previous post predicted that eventually we will be able to predict the origin of the universe, and, by golly, it looks as if we’ve done it. I didn’t think it would happen this quickly, but then one always tends to underestimate the power of Equations. A paper just came out today that predicts the spontaneous creation of the universe from nothing. From the abstract:
An interesting idea is that the universe could be spontaneously created from nothing, but no rigorous proof has been given. In this paper, we present such a proof based on the analytic solutions of the Wheeler-DeWitt equation (WDWE).
Aren’t Equations simply awe-inspiring? You’ll notice that rearranging the acronym in the above quote provides the inspiration for a catchy cliche for scientism: WWED (What Would Equations Do?).
You may have noticed some noise in the news recently about a telescope at the South Pole finding evidence for cosmic inflation. (Inflation is something that is supposed to have happened immediately after the Big Bang, where instead of the universe expanding near the rate at which it appears to be expanding today, the universe inflated at a much faster rate over a very short time period. It’s an idea that is supposed to explain the fact that the Cosmic Microwave Background is so smooth when there is no causal connection between its various parts. None of this matters much for the purposes of this post, but that’s the background in case you’re wondering.)
I was surprised to see this news, because I had just read a paper suggesting that we may need a new cosmological paradigm since the standard picture of inflation is now disfavored by observational data (data from other telescopes, not the data that was announced recently). Two of the authors on the paper are well-respected scientists from Harvard and Princeton (Abraham Loeb and Paul Steinhardt), and their criticisms are being addressed by the originators of the inflationary picture, so this is something that people are taking seriously. (It so happens that the announcement of the new results that generated the recent excitement came three days after the paper critical of inflation appeared online. This is rather coincidental and more than a little fishy, especially considering the fact that the new results contradict some of the previous ones. You’ll also notice in the news article linked above that the results weren’t expected to be announced for another year or so. My main purpose here, however, isn’t to engage in speculation about cosmological politics, but to highlight some of the criticisms of inflation that have been pointed out recently by serious thinkers.)
As described in the critical paper linked to above, the champions of inflation regard the standard inflationary picture to be outdated, and “they describe an alternative inflationary paradigm that has been developing in recent years and revises the assumptions and goals of inflation, and, as Linde suggests, perhaps of science generally. This makes clear that a schism has erupted between classic inflation and what might appropriately be called
postmodern inflation.” The critical paper then goes on to summarize the conceptual problems that have always existed in classic inflation. The worst of these conceptual problems is that “our observable universe is exponentially unlikely by a factor exceeding 10−1055 or more! Classic inflation is a catastrophic failure by this measure; numerically, it is one of the worst failures in the history of science.” They go on to say
How has a theory that fails catastrophically continued to survive in scientific discourse? For the most part, it is because… classic inflation seems to produce predictions that perfectly match observations. The point of  was to show that this is no longer the case.
(The paper referred to in this quote is another critical paper that came out about a year ago; the paper I’m discussing here is the response to the responses to that paper.)
Under the new paradigm, the solution to this catastrophic failure is to essentially change the way quantities are measured, and in particular to measure them in such a way that the theory matches the data, no matter what the data is, and no matter how much fine tuning the theory requires. As the authors point out, this is not really science.
In postmodern inflation, volume-weighting is abandoned in favor of selecting a measure a posteriori to fit observations. In this approach, the notion of generic predictions is sacrificed… In fact, observations cannot falsify postmodern inflation – failure to match observations leads instead to a change of measure. This places postmodern inflationary cosmology squarely outside the domain of normal science. Linde concurs , quoting Steven Weinberg , “Now we may be at a new turning point, a radical change in what we accept as a legitimate foundation for a physical theory.”
The final conclusion of the paper is this:
The scientific question we may be facing in the near future is: If classic inflation is outdated and a failure, are we willing to accept postmodern inflation, a construct that lies outside of normal science? Or is it time to seek an alternative cosmological paradigm?
Those are strong words, and it will be very interesting to see how this plays out.
One of the responses to the original criticisms highlights the fact that cosmology is not the only scientific discipline where these types of questions are relevant. One of the arguments put forth in favor of the postmodern paradigm by Guth (the originator of inflation), Kaiser and Nomura (from MIT and Berkeley, respectively), is very instructive:
We do not reject Darwinian evolution because it does not explain the actual origin of life; we do not reject big-bang nucleosynthesis because it does not explain the homogeneous thermal equilibrium initial state that it requires; and we should similarly not even consider rejecting the inflationary paradigm because it is not yet part of a complete solution to the ultimate mystery of the origin of the universe.
The primary feature of science that supposedly demands our respect is its ability to predict. We can predict the phases of the moon, which naturally implies that we can predict everything (the phases of the moon, the climate, the origin and fate of the universe, the origin of life, these are all pretty much the same kinds of things and if you’ll just give us a little more time, we’ll have the answer for you). Don’t miss the irony here: Guth et al are so confident in the power of science to provide answers that they are willing to defend a “scientific” paradigm that is not predictive.
A refreshing change of tone towards fundamentalists, the favorite whipping boy of modern writers:
It’s very easy to deflect any criticism of Christianity to fundamentalist crackpots. While affirmation of six-day creation may not be a test of orthodoxy, it is a good test of one’s loyalties, along with one’s willingness to invite ridicule from respectable people.
Creationists are finally getting some recognition. Not only does one of us have a slot in the upcoming meeting of the American Physical Society, but it’s also featured in a session entitled “New Directions in Astrophysics” (cutting edge, in other words). Click on the title for a link to the abstract:
It turns out that Hawking isn’t the originator of the Big Bang theory, but that factual error aside, I think this is likely to end up alongside the cosmological argument as one of the primary arguments for the existence of God. Did I just say recently that we creationists have a lot of work to do? I take it back.