What is learning for if it doesn't lead to wisdom?
That's a question worth asking in light of an ongoing cosmological street fight being waged (remarkably) in broad media daylight. The rumble tumbled into the public eye with Lawrence Krauss' new book A Universe From Nothing. But before the scathing New York Times review and an acerbic rebuttal in The Atlantic, this physics vs. philosophy smack-down was brewing in academic back alleys for decades. At stake is a critical question living deep inside the heart of modern foundational physics: What are the limits of science?
The battle began when David Albert — a well-known philosopher of science with an expertise in quantum mechanics — savaged Krauss' book in the Times (I touched on Albert's response in relation to science and religion when it first appeared). With Richard Dawkins providing an overheated afterward comparing the book to The Origin of The Species, there was no doubt an atheist/theist slugfest was in the offing.
But the bulk of Albert's review had nothing to do with religion and everything to do with basic philosophy. It was the very title of Krauss' book that Albert picked apart. Can physics explain how a Universe emerges from nothing? Not surprisingly, everything depends on which "nothing" you are talking about. That is where the knives came out.
Krauss invokes quantum field theory (QFT) and relies on its definition of nothing as the one that matters. Quantum fields are nature's most basic entity within the framework of modern physics. One of the coolest things about QFT's perspective is that all matter particles (quarks, electrons, etc.) are simply a manifestation or "configuration" of these background fields. Thus "nothing" from a quantum-field-theory perspective is nothing more a state of the field without particles.
In essence, Krauss was arguing that these "no particle" field states are (1) possible as a pre-condition for our universe and (2) inherently unstable. If you start with a universe with fields in a no-particle state — i.e., nothingness — then the laws of quantum mechanics allow them to spontaneously jump to configurations with lots of particles — i.e., something-ness.
So there you go. Start with nothing, add quantum field theory, get something. End of story. (You can throw in the end of God and religion, too).
David Albert was having none of it. As he correctly points out: Where do the fields come from? Better yet: Where do the laws of quantum mechanics come from? These are clearly meaningful questions even if, perhaps, they fall outside the domains of physics. The bulk of Albert's review is spent articulating how deeply Krauss had missed this point.
Krauss, in response, attacked the entire endeavor of philosophy.
In a widely panned Atlantic interview, Krauss refers to his philosophical critics as "moronic" and implies all philosophy of science to be useless. It was not a shining moment for Krauss (which is a shame because he is both a fine scientist and often a great public champion of science). Unfortunately Krauss is not alone in his blindly dismissive attitude concerning philosophy. There is also the case of Leonard Susskind.
Susskind is an accomplished theorist who has proposed changing the very nature of cosmological science in light of recent developments in String Theory. In his book The Cosmic Landscape, Susskind argued that physics must give up the ideal of predicting the nature of the one Universe we observe because String Theory can't make these kinds of predictions. It's a huge claim that draws upon a contentious idea known as the "anthropic principle." Ironically Susskind does not exert much effort dealing with the deep and deeply philosophical objections to this perspective. Waving his hands, Susskind poo-poo's philosophy's perspective on his radical idea saying "Frankly, I would have preferred to avoid the Philosophical discourse the Anthropic Principle excites". Yea, obviously.
Susskind and Krauss think they are channelling the great Richard Feynman in their dismissive attitudes toward philosophy. Richard Feynman was famously scornful of the philosophy of science. He thought it was immune to finding relevant results or making real progress. But the problem is that we aren't living in Richard Feynman's age of physics anymore. Something strange happened on the way to the modern intersection of cosmology and foundational physics. Some measure of philosophical sophistication seems helpful, if nothing else, in confronting this new landscape.
Its one thing for physicists exploring carbon nanotubes to say they have no use for philosophy. Their work lives or dies by experimental data that can be collected tomorrow. But over the last few decades, cosmology and foundational physics have become dominated by ideas that that appear to take a page from science fiction and, more importantly, remain firmly untethered to data.
Concepts like hidden dimensions of reality (string theory) or hidden infinite possible parallel universes (the multiverse) are radical revisions of the very concept of reality. Since detailed contact with experimental data might be decades away, theorists have relied mainly on mathematical consistency and "aesthetics" to guide their explorations. In light of these developments, it seems absurd to dismiss philosophy as having nothing to do with their endeavors.
Make no mistake, philosophy (and the philosophy of science) are not about doing science. Instead, these fields ask entirely different kinds of questions. They explore the relation between the possible and the actual, the correct links between an argument and it's conclusions or the tension between theoretical models and claims of evidence for those models.
Carbon-nanotube physicists are so deep within the traditional modes of empirical (i.e., data-driven) scientific investigation that they can happily ignore what goes on in the halls of philosophy. But as Krauss' example shows, cosmologists can push so hard and so far at the boundaries of fundamental concepts they cross over and fall prey to their own unspoken philosophical biases and misconceptions.
There are, of course, many cosmolgists/physicists (like Sean Carroll) who understand where the two domains both converge and diverge. Others, however, fail to get this point or its importance.
These are both exciting and dangerous times for the high flying fields of cosmology and foundational physics. With so little empirical grounding, "celebrity cosmologies" like the multiverse are skating on scientific thin ice. Given how much play these ideas get in the media (and their use, even, in the science vs. religion debate), it is incumbent on physicists who promulgate them to understand their full implications.
Dismissing philosophy, whose boundaries these scientists often cross with their grand claims, is a terrible way to map such exotic new terrain. As Krauss and others have found, it's easy to get lost out there.
You can keep up with more of what Adam Frank is thinking on Facebook and Twitter. His latest book is About Time: Cosmology and Culture at the Twilight of the Big Bang.
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