It’s an intentionally provocative title. But people overuse Popper’s ideas to the point of misuse, especially in physics. This is because people in physics today are philosophical pygmies. Please allow me to explain.
I’m currently reading Against Method by Paul Feyerabend. It validates what I do here on PlaneTalk, which makes me feel good, but that is not my point now. Normally, I don’t feel it is my place to comment on technical matters in current physics. It’s not my field, and I am not trained as a physicists. But I watched a series of talks last night (video 1, video 2, video 3, in that order), and read some really noxious stuff on Peter Woit’s comment section (make sure you read ALL the comments). Combined with reading Feyerabend, all of this has compelled me to express the following thoughts.
First, I want to briefly review how Karl Popper’s philosophy of science is being invoked in some physics circles. Then, I want to contrast Popper to Feyerabend, and the current generation of physicists to older generations of physicists. Then my point will have been made.
It’s Always Something
There are two places we hear Popper invoked:
- String theory
- Inflation in the context of Big Bang Theory
Let me briefly explain each. They will be brief because you can get as much info as you wish by Googling these topics.
String theory arose from the attempt to reconcile quantum mechanics and relativity. It seemed like a good idea when it was originally recognized that the formalism could be applied to “grand unification”. For example, the math naturally gave a vibration that could be interpreted as the “particle” associated with gravity, the graviton.
However, unlike any previous physics theory, elaborating these ideas led into territory where no math existed. So, theoretical physicists were forced to become mathematicians. Over the past couple decades the math to emerge has been “cumbersome”.
This math indicates that there should be some 10500 different ways to get particle physics, where our real world is just one of those 10500 possibilities. This is one of the theories of the multiverse that are all over mainstream science media at the moment.
This can be interpreted as a glass half empty or half full. The “glass half full” people are interpreting this to say that Nature is rich beyond belief and that the math is telling us that there is no one unique theory to describe our universe. Or, said differently, our universe is not unique, just as Earth is not unique. Just as there are many different types of planets, there are many different types of universes, with different laws of nature, different particles, different forces, and so on.
I say in passing, without elaborating, this is consistent with the Hindu view. When Hindus speak of the “unmanifest” and of Brahman, this implies a picture qualitatively similar to what string theorist have discovered. To say more must wait for another post.
The “glass half empty” people take the position that theories are supposed to make things simpler, not more complex. If a math model says there are 10500 universes, this is making things more complex and so is not a good theory.
Thinking that a theory should be as simple as possible is an aesthetic thing and thus is a matter of personal taste. But the “glass half empty” people try to justify their opinions by invoking Karl Popper’s philosophy of science, on which we now briefly digress…
One can read Wikipedia for Popper’s biography. His philosophy of science tried to determine what distinguished science from non-science. Popper defined the demarcation problem, discussed at the beginning of What Is Science?. Henry Bauer’s article discusses that there is no answer to the demarcation problem. However, this does not stop some people from invoking Popper’s disproven theory of science, which only indicates they do not know it is disproven.
Popper had legitimate concerns and attempted to solve one of the biggest problems associated with science. He sought to solve David Hume’s problem of induction.
Induction is when one takes many instances of something and makes a generalization from them. The common one is: the Sun has always risen in the East. One then induces the generalization: the Sun will always rise in the East. The problem with induction can be stated simply: all swans are white, that is, until one encounters a black swan.
Therefore, when scientists induce generalizations, they stand on shaky ground. There is no way whatsoever to prove an induced generalization is true. That is the problem of induction, first clearly articulated by David Hume.
Popper sought to solve this problem by creating a prescription for doing science that does not rely on induction. In short, Popper said that one should: (1) deduce some possibility using math, and (2) try to use experiments to prove that possibility is false.
One can always prove something is false. We can say with absolute certainly that all swans are not white, just because an example of a black swan exists.
When one follows Popper’s prescription, then one seeks to falsify a theory. That is the buzz word: falsify. Again, we can never prove an assertion is true. But we can always prove with 100% certainty that an assertion is false.
Back to the string theory issue: The “glass half empty” people are claiming string theory is useless because it “predicts” 10500 possible universes. It cannot be proven false since pretty much any universe one can imagine can be generated by string theory. String theory violates Popper’s idea of science.
Before critiquing Popper and those who advocate his ideas, let’s show how Popper is also used in discussions of inflation. The videos linked above are about inflation. Again, one may read the details on Wikipedia and learn more if one wishes.
Inflation arose in cosmology, in part, to account for the sameness of the visible universe in all directions. All parts of the universe appear to be in equilibrium. But this would be impossible because two parts of the universe at opposite extremes are so far apart that they effectively never “touched” each other to be able to come to equilibrium.
Inflation is the idea that, at some point in the past, the universe was small enough that all the parts “touched” each other and could achieve equilibrium. Then, after this, the universe blew up and enlarged really fast, like a giant balloon. This crazy idea was invoked to explain how the visible universe that we observe can be at equilibrium. There were other motivations for inflation too, but I am not discussing these here.
However, similar to string theory, as people have explored the mathematics behind inflation, they discovered that it too leads to a bunch of different universes. Video 1 above shows how this happens. So, one also gets multiverses from the mathematics of inflation.
Again, we get the “glass half empty” and “glass half full” people. In video 1, the theoretical physicists Paul Steinhardt is a “glass half empty” person. He thinks inflation is useless because it predicts all kinds of different universes. He explicitly invokes Popper’s idea of falsifiability. If you watch the debate in video 3, you see other physicists pushing back against Steinhardt.
Something in people resists being caged in by a single set of rules.
Popper Gets Caught In The Web
Popper tried to claim that his method is how all of science works in general. This was shown to be false by other philosophers. Perhaps the most famous refutation of Popper was Thomas Kuhn and his paradigms. Kuhn showed that Popper’s ideas were simply too simple.
Kuhn’s critique, in part, revolved around the idea of what a fact is. Popper’s view is based on the idea that a fact is neutral and objective. To Popper, a fact is just a fact. However, philosophy in general came to realize that there is no such thing as an isolated fact or an isolated anything. This is the philosophy of structuralism and its dogmatic child functionalism that I discussed previously.
Kuhn applied structuralism principles to the study of science by asserting the existence of paradigms. Paradigms are “webs of belief”; they are complex cognitive and social structures where every word and every idea is defined in terms of every other word and idea. As Marshall McLuhan said, “the medium is the message”. Therefore, a “fact” was only meaningful in terms of this invisible cognitive-social structure, the paradigm.
So, from Kuhn’s view, Popper is simply wrong. Science does not advance on the basis of theories being disqualified by facts. On Kuhn’s view, science proceeds by paradigms superseding each other and there are two major phases of science development. Revolutions occur when one paradigm wins out over another. “Normal science” happens after a given paradigm has triumphed, and gets to live in relative peace for a while before a new contender comes along to challenge it for the beliefs, the hearts and minds, of men.
During periods of “normal” science, when everyone shares the same paradigm, then a process like what Popper described can come into play. In “normal” science, everyone shares the same words and ideas, and it is possible for a “fact” to determine if one theory (i.e. model) is better than another.
The point here is, invoking Popper as a way to determine if inflation or string theory is good or bad is simply naïve. Doing so nowadays indicates that the invoker does not really know philosophy of science. This would be like me criticizing, say, virtual particles, for violating the law of conservation of energy, and not knowing about the uncertainty principle.
People who seek to suppress string theory and inflation by invoking Popper and saying these are not falsifiable theories do not offer up alternative paradigms. No, these people are also working within the current, mainstream paradigm. What they are really doing is being gadflies and provoking and irritating other people who accept inflation or string theory. A Popperian critique is not even disingenuous. It is naïve.
Just as Kuhn showed Popper’s theory of science was false, Feyerabend’s ideas showed Kuhn was too simple-minded. Feyerabend claimed that there is NO METHOD that distinguishes science from non-science. There is no criterion, method, procedure, or prescription that allows one to point to some activity and definitely and with 100% certainty say “THAT is science”.
Feyerabend sees science as a form of anarchy.
And he makes a convincing case. Read the citations in Bauer’s article, and you’ll see, no one has been able to refute Feyerabend as of this moment.
If we look at the line of thinking from Popper to Kuhn to Feyerabend, we see an increasingly realistic assessment of the history of science. Popper, to a large extent, idealized science and abstracted it from important historical details. Kuhn put the philosophy of science back into a historical context, but he didn’t go far enough. At any given moment, what is considered science and what is not considered science is very much a function of all the other things going on in the world. Feyerabend saw science in these terms.
To Feyerabend, science is a messy thing. All kinds of ideas float around against the backdrop of history and philosophy. Science, as a human activity, must survive along with all the other concurrent human activities. Scientists must vie for resources from the powers that be. They must convince and cajole the public that science and scientists have value. Scientists must constantly try to convince each other of the validity of what each is doing, and they compete for all manner of resources in whatever environment exists in the greater society.
Feyerabend sought to take all of this into account. As we can see Popper’s “facts” and “theories” subsumed by Kuhn’s paradigms, we see Kuhn’s paradigms subsumed by Feyerabend’s wide-open recognition that scientists are just people living in the world. Like all people, they too must eat, breath, and defecate. And their shit stinks like everyone else’s.
Science is not just one thing. It is an extremely complex bunch of history and stuff that coexists with all the other contingent, historical things in the world. There is nothing special about science to distinguishes it from other human activities.
If you look at how people invoke Popper in the string theory and the inflation debates, you can see Feyerabend’s ideas at work. These “glass half empty” Popperians are doing exactly the kind of political cajoling, intimidation, and other strategies Feyerabend discussed.
They should be embarrassed at invoking Popper and not knowing about all the water under the bridge since Popper’s time. Furthermore, they have the audacity to make fun of philosophy, which leads us to…
Young Buck, Old Buck
Hermann Weyl could cite Kant or Leibniz off the top of his head just as easily as he could cite Hilbert, Euclid, or Emmy Noether. Schrödinger thought long and hard about the mind-body problem (as did Weyl), quoted the Upanishads, and conceived the wave equation. Leibniz was, well, Leibniz. Einstein was worried about God, and even Bohr spoke in God’s defense against Einstein’s presumptions. Newton was obsessed with alchemy and knew a wider variety of world views than the current crop of philosophical pygmies who today have PhDs in physics.
The young bucks have dropped the ball compared to the old bucks. Why?
In large measure, it is the educational system. Schrödinger railed against the “more and more about less and less” form of education in Science and Humanism. He spoke of “educated brutes”. This was in the 1950s. It’s only gotten worse since then. Today, PhDs are churned out of the Universities like cars are popped off assembly lines. This method of education has now produced several generations of highly educated dumb people who have very little understanding of history, philosophy, and the links between history, philosophy, science, and religion.
Instead, we have standardization of thinking. We have the “standard model” of particle physics, the “standard model” of cosmology. In my own field we have the “central dogma” of molecular biology. All of these are symptoms of the same kind of standardization found in assembly lines. Today, we have assembly line PhDs. These are people with no appreciation that the intellect is a unified whole and that true intelligence cannot be pigeon-holed into this or that category.
As if learning a little philosophy, and more importantly, taking it seriously, is going to make one a worse scientist. Leibniz, Newton, Weyl, Schrödinger, Einstein, and other great physicists who have made lasting impact would likely be repulsed by the state of things today.
So, we can say that the modern physicists is but a parody, a degenerate form of what a physicists was in the past.
Hitting The Wall
In addition to assembly line PhDs, there is a thing called “saturation”. As a biologist, I am trained in this. Stuff cannot grow forever. There is always some limit or another on growth. There are limits on the energy we can access with our technology. There are limits on the precision of our measurements. We can only see so far by the very laws of physics. We have hit the boundaries of the observable universe. The amount of math that exists is finite. A single world view can only take one so far.
In these ways, physics is a victim of its own success. This is not to say that physics is at an end. But one must expect an asymptotic growth, where breakthroughs will come slower and slower and harder and harder. The current paradigms of modern physics, fragmented though they are presently, will inevitably saturate so that ever greater leaps of imaginations confined by these paradigms will produce ever smaller advances.
The in-fighting in physics is symptomatic of both factors: assembly line PhDs who are philosophical pygmies, and the limits of growth.
It’s not that Karl Popper was stupid. What is stupid are people with assembly line PhDs invoking Karl Popper when such people have only a partial idea of what Popper means today.
The current state of things reflects exactly the stuff Feyerabend discussed, including invoking worn-out philosophy to try to cajole and intimidate one’s peers to their point of view. Science is an anarchistic enterprise. The current crop of practitioners will suffer the indignation and keep on doing their “normal” science.
Everyone senses the need for some new “principle” to break out of the current paradigm with its obvious problems, and lead into the next one. What is ironic is that it is precisely philosophical insight that will allow this to happen. It will be a miracle if people who eschew and mock philosophy will be able to attain the needed insights.